Add multi-planar functions to GpuMemoryBuffer

ui/gfx/gpu_memory_buffer.h

Index: ui/gfx/gpu_memory_buffer.h
diff --git a/ui/gfx/gpu_memory_buffer.h b/ui/gfx/gpu_memory_buffer.h
index 3aa0964c36886233cb5ce7c474834abb51b60606..7c3860816b90ab7d2fd3ab738975d05fa5209967 100644
--- a/ui/gfx/gpu_memory_buffer.h
+++ b/ui/gfx/gpu_memory_buffer.h
@@ -61,11 +61,12 @@ class GFX_EXPORT GpuMemoryBuffer {
 
   virtual ~GpuMemoryBuffer() {}
 
-  // Maps the buffer into the client's address space so it can be written to by
-  // the CPU. This call may block, for instance if the GPU needs to finish
-  // accessing the buffer or if CPU caches need to be synchronized. Returns NULL
-  // on failure.
-  virtual void* Map() = 0;
+  // Maps each plane of the buffer into the client's address space so it can be
+  // written to by the CPU. A pointer to plane K is stored at index K-1 of the
+  // |data| array. This call may block, for instance if the GPU needs to finish
+  // accessing the buffer or if CPU caches need to be synchronized. Returns
+  // false on failure.
+  virtual bool Map(void** data) = 0;
 
   // Unmaps the buffer. It's illegal to use the pointer returned by Map() after
   // this has been called.
@@ -77,8 +78,10 @@ class GFX_EXPORT GpuMemoryBuffer {
   // Returns the format for the buffer.
   virtual Format GetFormat() const = 0;
 
-  // Returns the stride in bytes for the buffer.
-  virtual uint32 GetStride() const = 0;
+  // Fills the stride in bytes for the each plane of the buffer. The stride of
+  // plane K is stored at index K-1 of the |stride| array. Returns
+  // false on failure.
+  virtual void GetStride(uint32* stride) const = 0;
 
   // Returns a platform specific handle for this buffer.
   virtual GpuMemoryBufferHandle GetHandle() const = 0;