Add ownership edges between HostSharedBitmap and shared memory

cc/resources/shared_bitmap.h

Index: cc/resources/shared_bitmap.h
diff --git a/cc/resources/shared_bitmap.h b/cc/resources/shared_bitmap.h
index 464ac5c6d4c020ed3cab876bc69c50a303843171..faacae9124b0d7d9783a1ac05c39fe5ed1af3751 100644
--- a/cc/resources/shared_bitmap.h
+++ b/cc/resources/shared_bitmap.h
@@ -14,6 +14,12 @@
 #include "gpu/command_buffer/common/mailbox.h"
 #include "ui/gfx/geometry/size.h"
 
+namespace base {
+
+class SharedMemory;
+
+}  // namespace base
+
 namespace cc {
 typedef gpu::Mailbox SharedBitmapId;
 
@@ -22,12 +28,16 @@ GetSharedBitmapGUIDForTracing(const SharedBitmapId& bitmap_id);
 
 class CC_EXPORT SharedBitmap {
  public:
-  SharedBitmap(uint8_t* pixels, const SharedBitmapId& id);
+  SharedBitmap(uint8_t* pixels,
+               base::SharedMemory* shared_memory,
+               const SharedBitmapId& id);
 
   virtual ~SharedBitmap();
 
   uint8_t* pixels() { return pixels_; }
 
+  base::SharedMemory* shared_memory() const { return shared_memory_; }
+
   const SharedBitmapId& id() { return id_; }
 
   // Returns true if the size is valid and false otherwise.
@@ -45,6 +55,7 @@ class CC_EXPORT SharedBitmap {
 
  private:
   uint8_t* pixels_;
+  base::SharedMemory* shared_memory_;
   SharedBitmapId id_;
 
   DISALLOW_COPY_AND_ASSIGN(SharedBitmap);