aw: Add versions to public function tables

android_webview/public/browser/draw_gl.h

Index: android_webview/public/browser/draw_gl.h
diff --git a/android_webview/public/browser/draw_gl.h b/android_webview/public/browser/draw_gl.h
index 4a43523593ac151fd2c67e580dbdfd37be52cb14..d62375fc5bdeac0fd632bd00ff4c86e75667ee15 100644
--- a/android_webview/public/browser/draw_gl.h
+++ b/android_webview/public/browser/draw_gl.h
@@ -86,8 +86,11 @@ typedef void* AwGetNativeBufferFunction(long buffer_id);
 // Called to get the stride of the buffer
 typedef unsigned int AwGetStrideFunction(long buffer_id);
 
+static const int kAwDrawGLFunctionTableVersion = 1;

[hush (inactive), 2014/07/31 21:03:50]

what is the circumstance that AwDrawGLFunctionTableVersion is different from
AwDrawGLInfoVersion? Should they always be the same version?

[hush (inactive), 2014/07/31 21:08:40]

I guess every time you add something to the struct, you need to increase the
version number by 1. And you are not supposed to delete members from the struct.
Right?
On 2014/07/31 21:03:50, hush wrote:

[boliu, 2014/07/31 21:09:38]

They can change independently. For example if we switch to idle upload, we can
drop all the gralloc functions from the table below, which is ehh...everything.
But nothing changes to AwDrawGLInfoVersion

[boliu, 2014/07/31 21:10:46]

Right that's the idea. And you can't access new members based on version.

Binary stability..

+
 // Set of functions used in rendering in hardware mode
 struct AwDrawGLFunctionTable {
+  int version;
   AwCreateGraphicBufferFunction* create_graphic_buffer;
   AwReleaseGraphicBufferFunction* release_graphic_buffer;
   AwMapFunction* map;