Add a helper method to gl::RenderTarget to return the extents of the texture (width/height/depth).

src/libGLESv2/renderer/RenderTarget.h

@@ -11,6 +11,7 @@
 #define LIBGLESV2_RENDERER_RENDERTARGET_H_
 
 #include "common/angleutils.h"
+#include "libGLESv2/angletypes.h"
 
 namespace rx
 {
@@ -29,12 +30,13 @@ class RenderTarget
 
     virtual ~RenderTarget() {};
 
-    GLsizei getWidth() { return mWidth; }
-    GLsizei getHeight() { return mHeight; }
-    GLsizei getDepth() { return mDepth; }
-    GLenum getInternalFormat() { return mInternalFormat; }
-    GLenum getActualFormat() { return mActualFormat; }
-    GLsizei getSamples() { return mSamples; }
+    GLsizei getWidth() const { return mWidth; }
+    GLsizei getHeight() const { return mHeight; }
+    GLsizei getDepth() const { return mDepth; }
+    GLenum getInternalFormat() const { return mInternalFormat; }
+    GLenum getActualFormat() const { return mActualFormat; }
+    GLsizei getSamples() const { return mSamples; }
+    gl::Extents getExtents() const { return gl::Extents(mWidth, mHeight, mDepth); }
 
     virtual void invalidate(GLint x, GLint y, GLsizei width, GLsizei height) = 0;