Add logic to ResourceProvider to correctly lock GpuMemoryBuffer Resources.

cc/resources/resource_provider.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_RESOURCES_RESOURCE_PROVIDER_H_
 #define CC_RESOURCES_RESOURCE_PROVIDER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 297 matching lines @@
 
    private:
     ResourceProvider* resource_provider_;
     ResourceProvider::Resource* resource_;
     SkBitmap sk_bitmap_;
     base::ThreadChecker thread_checker_;
 
     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,
                                    ResourceId resource_id);
     ~ScopedWriteLockGpuMemoryBuffer();
 
     gfx::GpuMemoryBuffer* GetGpuMemoryBuffer();
 
    private:
     ResourceProvider* resource_provider_;
@@ skipping 353 matching lines @@
   // A process-unique ID used for disambiguating memory dumps from different
   // resource providers.
   int tracing_id_;
 
   DISALLOW_COPY_AND_ASSIGN(ResourceProvider);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_RESOURCE_PROVIDER_H_