Mac: Use GpuMemoryBuffers by default

content/browser/gpu/compositor_util.cc

Index: content/browser/gpu/compositor_util.cc
diff --git a/content/browser/gpu/compositor_util.cc b/content/browser/gpu/compositor_util.cc
index 1b77f8b9ccbf4080be85bf2013f4fb30e66dbe25..10f507b3660d96c99bed46d386dcbacdf7f1531f 100644
--- a/content/browser/gpu/compositor_util.cc
+++ b/content/browser/gpu/compositor_util.cc
@@ -12,6 +12,7 @@
 #include "build/build_config.h"
 #include "cc/base/math_util.h"
 #include "cc/base/switches.h"
+#include "content/browser/gpu/browser_gpu_memory_buffer_manager.h"
 #include "content/browser/gpu/gpu_data_manager_impl.h"
 #include "content/public/common/content_switches.h"
 #include "gpu/config/gpu_feature_type.h"
@@ -219,8 +220,30 @@ bool IsPartialRasterEnabled() {
 bool IsGpuMemoryBufferCompositorResourcesEnabled() {
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
-  return command_line.HasSwitch(
-      switches::kEnableGpuMemoryBufferCompositorResources);
+  if (command_line.HasSwitch(
+          switches::kEnableGpuMemoryBufferCompositorResources)) {
+    return true;
+  }
+  if (command_line.HasSwitch(
+          switches::kDisableGpuMemoryBufferCompositorResources)) {
+    return false;
+  }
+
+  // Native GPU memory buffers are required.
+  if (!BrowserGpuMemoryBufferManager::IsNativeGpuMemoryBuffersEnabled())
+    return false;
+
+  // GPU rasterization does not support GL_TEXTURE_RECTANGLE_ARB, which is
+  // required by GpuMemoryBuffers on Mac.
+  // http://crbug.com/551072
+  if (IsForceGpuRasterizationEnabled() || IsGpuRasterizationEnabled())
+    return false;
+
+#if defined(OS_MACOSX)
+  return true;
+#else
+  return false;
+#endif
 }
 
 bool IsGpuRasterizationEnabled() {