Allow PPB_ImageData_Impl to be created in a way that is compatible with unittests

content/renderer/pepper/ppb_image_data_impl.h

Index: content/renderer/pepper/ppb_image_data_impl.h
diff --git a/content/renderer/pepper/ppb_image_data_impl.h b/content/renderer/pepper/ppb_image_data_impl.h
index a16bbfa104b2a9cd9d06a5bffab82dbb8ba57383..578854cfe80998dae89630ca526543053ee9ac9a 100644
--- a/content/renderer/pepper/ppb_image_data_impl.h
+++ b/content/renderer/pepper/ppb_image_data_impl.h
@@ -51,8 +51,15 @@ class CONTENT_EXPORT PPB_ImageData_Impl
   // If you call this constructor, you must also call Init before use. Normally
   // you should use the static Create function, but this constructor is needed
   // for some internal uses of ImageData (like Graphics2D).
+  // |is_browser_allocated| indicates whether the backing shared memory should
+  // be allocated by the browser process.
   PPB_ImageData_Impl(PP_Instance instance,
-                     PPB_ImageData_Shared::ImageDataType type);
+                     PPB_ImageData_Shared::ImageDataType type,
+                     bool is_browser_allocated);
+
+  // Returns true if the ImageData shared memory should be allocated in the
+  // browser process for the current platform.
+  static bool IsBrowserAllocated(ImageDataType format);
 
   bool Init(PP_ImageDataFormat format,
             int width, int height,
@@ -102,7 +109,7 @@ class CONTENT_EXPORT PPB_ImageData_Impl
 
 class ImageDataPlatformBackend : public PPB_ImageData_Impl::Backend {
  public:
-  ImageDataPlatformBackend();
+  ImageDataPlatformBackend(bool is_browser_allocated);
   virtual ~ImageDataPlatformBackend();
 
   // PPB_ImageData_Impl::Backend implementation.
@@ -124,6 +131,8 @@ class ImageDataPlatformBackend : public PPB_ImageData_Impl::Backend {
   int height_;
   scoped_ptr<TransportDIB> dib_;
 
+  bool is_browser_allocated_;
+
   // When the device is mapped, this is the image. Null when umapped.
   scoped_ptr<SkCanvas> mapped_canvas_;