Fix about:gpu's wrong status of accelerated-canvas-2d.

The decision whether to support accelerated-canvas-2d is made on the renderer side.  This CL duplicates the same logic on the browser side, so about:gpu reports the correct feature status.

An alternative is to add an IPC messege to query renderer side about the feature status, which isn't very appealing.

BUG=100722
TEST=about:gpu
Review URL: http://codereview.chromium.org/8341036

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@107362 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 19 insertions, 2 deletions

diff --git a/content/browser/gpu/gpu_data_manager.cc b/content/browser/gpu/gpu_data_manager.cc
index 8bd3bbd..991daac 100644
--- a/content/browser/gpu/gpu_data_manager.cc
+++ b/content/browser/gpu/gpu_data_manager.cc
@@ -264,8 +264,10 @@ Value* GpuDataManager::GetFeatureStatus() {
       {
           "2d_canvas",
           flags & GpuFeatureFlags::kGpuFeatureAccelerated2dCanvas,
-          user_flags_.disable_accelerated_2d_canvas(),
-          "Accelerated 2D canvas has been disabled at the command line.",
+          user_flags_.disable_accelerated_2d_canvas() ||
+          !supportsAccelerated2dCanvas(),
+          "Accelerated 2D canvas is unavailable: either disabled at the command"
+          " line or not supported by the current system.",
           true
       },
       {
@@ -762,3 +764,14 @@ bool GpuDataManager::Merge(content::GPUInfo* object,
   }
   return changed;
 }
+
+bool GpuDataManager::supportsAccelerated2dCanvas() const {
+  if (gpu_info_.can_lose_context)
+    return false;
+#if defined(USE_SKIA)
+  return true;
+#else
+  return false;
+#endif
+}
+
diff --git a/content/browser/gpu/gpu_data_manager.h b/content/browser/gpu/gpu_data_manager.h
index e92f716..b91e10c 100644
--- a/content/browser/gpu/gpu_data_manager.h
+++ b/content/browser/gpu/gpu_data_manager.h
@@ -187,6 +187,10 @@ class CONTENT_EXPORT GpuDataManager {
   // and gl_renderer.
   static bool Merge(content::GPUInfo* object, const content::GPUInfo& other);
 
+  // Determin if accelerated-2d-canvas is supported, which depends on whether
+  // lose_context could happen and whether skia is the backend.
+  bool supportsAccelerated2dCanvas() const;
+
   bool complete_gpu_info_already_requested_;
 
   GpuFeatureFlags gpu_feature_flags_;