Update GPU memory buffers to use StrideInBytes internally.

ui/gl/gl_image_memory.cc

Index: ui/gl/gl_image_memory.cc
diff --git a/ui/gl/gl_image_memory.cc b/ui/gl/gl_image_memory.cc
index 0a67e000665b6a5806a0f935f61e02faaf540a15..57635660efba41de2d59e8ddc450123d3d380413 100644
--- a/ui/gl/gl_image_memory.cc
+++ b/ui/gl/gl_image_memory.cc
@@ -100,11 +100,11 @@ GLImageMemory::~GLImageMemory() {
 }
 
 // static
-size_t GLImageMemory::BytesPerPixel(gfx::GpuMemoryBuffer::Format format) {
+size_t GLImageMemory::BitsPerPixel(gfx::GpuMemoryBuffer::Format format) {
   switch (format) {
     case gfx::GpuMemoryBuffer::RGBA_8888:
     case gfx::GpuMemoryBuffer::BGRA_8888:
-      return 4;
+      return 32;
     case gfx::GpuMemoryBuffer::RGBX_8888:
       NOTREACHED();
       return 0;