Support ARGB_8888 by default in GLHelperReadbackSupport

This is a work around for a driver bug on Galaxy Nexus

BUG=349667

Review URL: https://codereview.chromium.org/184103037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255386 0039d316-1c4b-4281-b951-d872f2087c98

content/common/gpu/client/gl_helper_readback_support.cc

@@ -37,7 +37,8 @@ void GLHelperReadbackSupport::CheckForReadbackSupport(
       supports_format = SupportsFormat(GL_RGB, GL_UNSIGNED_SHORT_5_6_5);
       break;
     case SkBitmap::kARGB_8888_Config:
-      supports_format = SupportsFormat(GL_RGBA, GL_UNSIGNED_BYTE);
+      // This is the baseline, assume always true.
+      supports_format = true;
       break;
     case SkBitmap::kARGB_4444_Config:
       supports_format = false;