Add scale factor and 2x resources from webkit and plumb through to ContentClient.

webkit/tools/test_shell/test_shell_mac.mm

Index: webkit/tools/test_shell/test_shell_mac.mm
diff --git a/webkit/tools/test_shell/test_shell_mac.mm b/webkit/tools/test_shell/test_shell_mac.mm
index a5a556ca1dee6d1add51cd687f75ed738b10d75b..e5f749d26eef1d76c1e6a90212d709ea729977b2 100644
--- a/webkit/tools/test_shell/test_shell_mac.mm
+++ b/webkit/tools/test_shell/test_shell_mac.mm
@@ -631,6 +631,11 @@ string16 TestShellWebKitInit::GetLocalizedString(int message_id) {
 }
 
 base::StringPiece TestShellWebKitInit::GetDataResource(int resource_id) {
+  return base::StringPiece();
+}
+
+base::StringPiece TestShellWebKitInit::GetImageResource(int resource_id,
+                                                        float scale_factor) {
   switch (resource_id) {
   case IDR_BROKENIMAGE: {
     // Use webkit's broken image icon (16x16)
@@ -677,6 +682,7 @@ base::StringPiece TestShellWebKitInit::GetDataResource(int resource_id) {
   case IDR_INPUT_SPEECH:
   case IDR_INPUT_SPEECH_RECORDING:
   case IDR_INPUT_SPEECH_WAITING:
+    // TODO(flackr): Pass scale_factor to ResourceProvider.
     return TestShell::ResourceProvider(resource_id);
 
   default: