Implement the gamepad API in the IPC proxy

ppapi/examples/gamepad/gamepad.cc

Index: ppapi/examples/gamepad/gamepad.cc
diff --git a/ppapi/examples/gamepad/gamepad.cc b/ppapi/examples/gamepad/gamepad.cc
index 96a127cc04d830166c0406ff2f55785ec6df99de..4fedc0be47ac131ec4e880e35c9597808d1ded47 100644
--- a/ppapi/examples/gamepad/gamepad.cc
+++ b/ppapi/examples/gamepad/gamepad.cc
@@ -85,7 +85,7 @@ class MyInstance : public pp::Instance {
   }
 
   pp::ImageData PaintImage(const pp::Size& size) {
-    pp::ImageData image(this, PP_IMAGEDATAFORMAT_BGRA_PREMUL, size, false);
+    pp::ImageData image(this, PP_IMAGEDATAFORMAT_BGRA_PREMUL, size, true);

[raymes, 2012/09/05 21:05:57]

What's this for?

[brettw, 2012/09/05 21:25:51]

This was a bug in the example where it doesn't request that the data be cleared,
but doesn't clear it itself. When we wrote it this was OK since we always
cleared. My new image data cache means it isn't always cleared and the example
has some painting artifacts.

     if (image.is_null())
       return image;