--- a/gfx/gl/GLContext.cpp
+++ b/gfx/gl/GLContext.cpp
@@ -1012,25 +1012,19 @@ GLContext::InitWithPrefixImpl(const char
         if (mVendor == GLVendor::Intel) {
             // see bug 737182 for 2D textures, bug 684882 for cube map textures.
             mMaxTextureSize        = std::min(mMaxTextureSize,        4096);
             mMaxCubeMapTextureSize = std::min(mMaxCubeMapTextureSize, 512);
             // for good measure, we align renderbuffers on what we do for 2D textures
             mMaxRenderbufferSize   = std::min(mMaxRenderbufferSize,   4096);
             mNeedsTextureSizeChecks = true;
         } else if (mVendor == GLVendor::NVIDIA) {
-            if (nsCocoaFeatures::OnMountainLionOrLater()) {
-                // See bug 879656.  8192 fails, 8191 works.
-                mMaxTextureSize = std::min(mMaxTextureSize, 8191);
-                mMaxRenderbufferSize = std::min(mMaxRenderbufferSize, 8191);
-            } else {
-                // See bug 877949.
-                mMaxTextureSize = std::min(mMaxTextureSize, 4096);
-                mMaxRenderbufferSize = std::min(mMaxRenderbufferSize, 4096);
-            }
+            // See bug 879656.  8192 fails, 8191 works.
+            mMaxTextureSize = std::min(mMaxTextureSize, 8191);
+            mMaxRenderbufferSize = std::min(mMaxRenderbufferSize, 8191);
 
             // Part of the bug 879656, but it also doesn't hurt the 877949
             mNeedsTextureSizeChecks = true;
         }
     }
 #endif
 #ifdef MOZ_X11
     if (mWorkAroundDriverBugs) {

--- a/gfx/gl/GLContextFeatures.cpp
+++ b/gfx/gl/GLContextFeatures.cpp
@@ -1,20 +1,16 @@
 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "GLContext.h"
 #include "nsPrintfCString.h"
 
-#ifdef XP_MACOSX
-#include "nsCocoaFeatures.h"
-#endif
-
 namespace mozilla {
 namespace gl {
 
 const size_t kMAX_EXTENSION_GROUP_SIZE = 5;
 
 enum class GLVersion : uint32_t {
     NONE  = 0,   // Feature is not supported natively by GL
     GL1_2 = 120,
@@ -880,26 +876,16 @@ GLContext::InitFeatures()
     if (ShouldDumpExts()) {
         for (size_t featureId = 0; featureId < size_t(GLFeature::EnumMax); featureId++) {
             GLFeature feature = GLFeature(featureId);
             printf_stderr("[%s] Feature::%s\n",
                           IsSupported(feature) ? "enabled" : "disabled",
                           GetFeatureName(feature));
         }
     }
-
-    if (WorkAroundDriverBugs()) {
-#ifdef XP_MACOSX
-        // MacOSX 10.6 reports to support EXT_framebuffer_sRGB and EXT_texture_sRGB but
-        // fails to convert from sRGB to linear when reading from an sRGB texture attached
-        // to an FBO. (bug 843668)
-        if (!nsCocoaFeatures::OnLionOrLater())
-            MarkUnsupported(GLFeature::sRGB_framebuffer);
-#endif // XP_MACOSX
-    }
 }
 
 void
 GLContext::MarkUnsupported(GLFeature feature)
 {
     mAvailableFeatures[size_t(feature)] = false;
 
     const FeatureInfo& featureInfo = GetFeatureInfo(feature);

--- a/gfx/layers/opengl/CompositorOGL.cpp
+++ b/gfx/layers/opengl/CompositorOGL.cpp
@@ -41,20 +41,16 @@
 #include "GLReadTexImageHelper.h"
 #include "GLBlitTextureImageHelper.h"
 #include "HeapCopyOfStackArray.h"
 
 #if MOZ_WIDGET_ANDROID
 #include "TexturePoolOGL.h"
 #endif
 
-#ifdef XP_MACOSX
-#include "nsCocoaFeatures.h"
-#endif
-
 #include "GeckoProfiler.h"
 
 namespace mozilla {
 
 using namespace std;
 using namespace gfx;
 
 namespace layers {
@@ -1434,31 +1430,16 @@ CompositorOGL::DrawQuad(const Rect& aRec
       BindAndDrawQuadWithTextureRect(program,
                                      aRect,
                                      effectComponentAlpha->mTextureCoords,
                                      effectComponentAlpha->mOnBlack);
 
       // Pass 2.
       gl()->fBlendFuncSeparate(LOCAL_GL_ONE, LOCAL_GL_ONE,
                                LOCAL_GL_ONE, LOCAL_GL_ONE);
-
-#ifdef XP_MACOSX
-      if (gl()->WorkAroundDriverBugs() &&
-          gl()->Vendor() == GLVendor::NVIDIA &&
-          !nsCocoaFeatures::OnMavericksOrLater()) {
-        // Bug 987497: With some GPUs the nvidia driver on 10.8 and below
-        // won't pick up the TexturePass2 uniform change below if we don't do
-        // something to force it. Re-activating the shader seems to be one way
-        // of achieving that.
-        GLint program;
-        mGLContext->fGetIntegerv(LOCAL_GL_CURRENT_PROGRAM, &program);
-        mGLContext->fUseProgram(program);
-      }
-#endif
-
       program->SetTexturePass2(true);
       BindAndDrawQuadWithTextureRect(program,
                                      aRect,
                                      effectComponentAlpha->mTextureCoords,
                                      effectComponentAlpha->mOnBlack);
 
       mGLContext->fBlendFuncSeparate(LOCAL_GL_ONE, LOCAL_GL_ONE_MINUS_SRC_ALPHA,
                                      LOCAL_GL_ONE, LOCAL_GL_ONE_MINUS_SRC_ALPHA);

--- a/gfx/thebes/gfxFontEntry.cpp
+++ b/gfx/thebes/gfxFontEntry.cpp
@@ -33,20 +33,16 @@
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/Services.h"
 #include "mozilla/Telemetry.h"
 #include "gfxSVGGlyphs.h"
 #include "gfxMathTable.h"
 #include "gfx2DGlue.h"
 
-#if defined(XP_MACOSX)
-#include "nsCocoaFeatures.h"
-#endif
-
 #include "cairo.h"
 
 #include "harfbuzz/hb.h"
 #include "harfbuzz/hb-ot.h"
 #include "graphite2/Font.h"
 
 #include <algorithm>
 
@@ -1770,23 +1766,16 @@ gfxFontFamily::ReadFaceNames(gfxPlatform
 {
     // if all needed names have already been read, skip
     if (mOtherFamilyNamesInitialized &&
         (mFaceNamesInitialized || !aNeedFullnamePostscriptNames))
         return;
 
     bool asyncFontLoaderDisabled = false;
 
-#if defined(XP_MACOSX)
-    // bug 975460 - async font loader crashes sometimes under 10.6, disable
-    if (!nsCocoaFeatures::OnLionOrLater()) {
-        asyncFontLoaderDisabled = true;
-    }
-#endif
-
     if (!mOtherFamilyNamesInitialized &&
         aFontInfoData &&
         aFontInfoData->mLoadOtherNames &&
         !asyncFontLoaderDisabled)
     {
         AutoTArray<nsString,4> otherFamilyNames;
         bool foundOtherNames =
             aFontInfoData->GetOtherFamilyNames(mName, otherFamilyNames);

--- a/gfx/thebes/gfxMacPlatformFontList.mm
+++ b/gfx/thebes/gfxMacPlatformFontList.mm
@@ -1201,20 +1201,17 @@ public:
                 bool aLoadCmaps) :
         FontInfoData(aLoadOtherNames, aLoadFaceNames, aLoadCmaps)
     {}
 
     virtual ~MacFontInfo() {}
 
     virtual void Load() {
         nsAutoreleasePool localPool;
-        // bug 975460 - async font loader crashes sometimes under 10.6, disable
-        if (nsCocoaFeatures::OnLionOrLater()) {
-            FontInfoData::Load();
-        }
+        FontInfoData::Load();
     }
 
     // loads font data for all members of a given family
     virtual void LoadFontFamilyData(const nsAString& aFamilyName);
 };
 
 void
 MacFontInfo::LoadFontFamilyData(const nsAString& aFamilyName)

--- a/gfx/thebes/gfxPlatformMac.cpp
+++ b/gfx/thebes/gfxPlatformMac.cpp
@@ -19,17 +19,16 @@
 #include "mozilla/Preferences.h"
 #include "mozilla/VsyncDispatcher.h"
 #include "qcms.h"
 #include "gfx2DGlue.h"
 
 #include <dlfcn.h>
 #include <CoreVideo/CoreVideo.h>
 
-#include "nsCocoaFeatures.h"
 #include "mozilla/layers/CompositorBridgeParent.h"
 #include "VsyncSource.h"
 
 using namespace mozilla;
 using namespace mozilla::gfx;
 
 // cribbed from CTFontManager.h
 enum {
@@ -365,24 +364,16 @@ gfxPlatformMac::ReadAntiAliasingThreshol
         }
         CFRelease(prefValue);
     }
 
     return threshold;
 }
 
 bool
-gfxPlatformMac::UseProgressivePaint()
-{
-  // Progressive painting requires cross-process mutexes, which don't work so
-  // well on OS X 10.6 so we disable there.
-  return nsCocoaFeatures::OnLionOrLater() && gfxPlatform::UseProgressivePaint();
-}
-
-bool
 gfxPlatformMac::AccelerateLayersByDefault()
 {
   return true;
 }
 
 // This is the renderer output callback function, called on the vsync thread
 static CVReturn VsyncCallback(CVDisplayLinkRef aDisplayLink,
                               const CVTimeStamp* aNow,

--- a/gfx/thebes/gfxPlatformMac.h
+++ b/gfx/thebes/gfxPlatformMac.h
@@ -71,17 +71,16 @@ public:
 
     bool RequiresAcceleratedGLContextForCompositorOGL() const override {
       // On OS X in a VM, unaccelerated CompositorOGL shows black flashes, so we
       // require accelerated GL for CompositorOGL but allow unaccelerated GL for
       // BasicCompositor.
       return true;
     }
 
-    virtual bool UseProgressivePaint() override;
     virtual already_AddRefed<mozilla::gfx::VsyncSource> CreateHardwareVsyncSource() override;
 
     // lower threshold on font anti-aliasing
     uint32_t GetAntiAliasingThreshold() { return mFontAntiAliasingThreshold; }
 
 protected:
     bool AccelerateLayersByDefault() override;