Add logic to ResourceProvider to correctly lock GpuMemoryBuffer Resources.

cc/resources/resource_provider.h

Index: cc/resources/resource_provider.h
diff --git a/cc/resources/resource_provider.h b/cc/resources/resource_provider.h
index 56c3a625a097e6c93539dc8dc8bf188d785233a5..05636e40e0cc53671cf23d3a9f8bbff95c129126 100644
--- a/cc/resources/resource_provider.h
+++ b/cc/resources/resource_provider.h
@@ -315,6 +315,23 @@ class CC_EXPORT ResourceProvider
     DISALLOW_COPY_AND_ASSIGN(ScopedWriteLockSoftware);
   };
 
+  class CC_EXPORT ScopedReadLockGpuMemoryBuffer {
+   public:
+    ScopedReadLockGpuMemoryBuffer(ResourceProvider* resource_provider,
+                                  ResourceId resource_id);
+    virtual ~ScopedReadLockGpuMemoryBuffer();
+
+    unsigned texture_id() const { return resource_->gl_id; }
+    bool IsInUseByMacOSWindowServer() const;

[ccameron, 2016/05/17 03:36:38]

This should have a GetGpuMemoryBuffer accessor, like
ScopedWriteLockGpuMemoryBuffer -- no need to have a IsInUse function here as
well.

[erikchen, 2016/05/17 22:13:21]

N/A

+
+   private:
+    ResourceProvider* resource_provider_;
+    ResourceId resource_id_;
+    const ResourceProvider::Resource* resource_;
+
+    DISALLOW_COPY_AND_ASSIGN(ScopedReadLockGpuMemoryBuffer);
+  };
+
   class CC_EXPORT ScopedWriteLockGpuMemoryBuffer {
    public:
     ScopedWriteLockGpuMemoryBuffer(ResourceProvider* resource_provider,