Allow the resource cache to (indirectly) flush the InOrderDrawBuffer

src/gpu/GrResourceCache.h

Index: src/gpu/GrResourceCache.h
===================================================================
--- src/gpu/GrResourceCache.h	(revision 9928)
+++ src/gpu/GrResourceCache.h	(working copy)
@@ -238,6 +238,17 @@
     void setLimits(int maxResource, size_t maxResourceBytes);
 
     /**
+     *  Set the callback the cache should use when it is still over budget
+     *  after a purge. The 'data' provided here will be passed back to the 
+     *  callback.

[bsalomon, 2013/07/09 17:43:25]

Maybe mention that the cache will attempt to purge any newly freed resources
after the CB?

Q: Should callback return a value indicating whether it successfully unrefed
anything? We don't detect this today...

[robertphillips, 2013/07/10 10:15:13]

Done.

I expanded the comment and made the CB now return a boolean.

+     */
+    typedef void (*PFOverbudgetCB)(void* data);
+    void setOverbudgetCallback(PFOverbudgetCB overbudgetCB, void* data) {
+        fOverbudgetCB = overbudgetCB;
+        fOverbudgetData = data;
+    }
+
+    /**
      * Returns the number of bytes consumed by cached resources.
      */
     size_t getCachedResourceBytes() const { return fEntryBytes; }
@@ -360,8 +371,13 @@
     size_t fClientDetachedBytes;
 
     // prevents recursive purging
-    bool fPurging;
+    bool           fPurging;
 
+    PFOverbudgetCB fOverbudgetCB;
+    void*          fOverbudgetData;
+
+    void internalPurge();
+
 #if GR_DEBUG
     static size_t countBytes(const SkTInternalLList<GrResourceEntry>& list);
 #endif