Send array of paint rects and bitmaps as opposed to a Union

chrome/browser/renderer_host/backing_store.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/renderer_host/backing_store.h"
 
 #include "base/sys_info.h"
 #include "chrome/browser/renderer_host/render_widget_host.h"
 #include "chrome/common/chrome_constants.h"
 
@@ skipping 33 matching lines @@
     cache->Put(host, backing_store);
   }
   return backing_store;
 }
 
 }  // namespace
 
 // BackingStoreManager ---------------------------------------------------------
 
 // static
+int BackingStore::kMaxBitmapLengthAllowed = 100000;
+
 BackingStore* BackingStoreManager::GetBackingStore(
     RenderWidgetHost* host,
     const gfx::Size& desired_size) {
   BackingStore* backing_store = Lookup(host);
   if (backing_store) {
     // If we already have a backing store, then make sure it is the correct
     // size.
     if (backing_store->size() == desired_size)
       return backing_store;
     backing_store = NULL;
   }
 
   return backing_store;
 }
 
 // static
 BackingStore* BackingStoreManager::PrepareBackingStore(
     RenderWidgetHost* host,
     const gfx::Size& backing_store_size,
     base::ProcessHandle process_handle,
     TransportDIB* bitmap,
     const gfx::Rect& bitmap_rect,
+    const gfx::Rect& paint_rect,
     bool* needs_full_paint) {
   BackingStore* backing_store = GetBackingStore(host, backing_store_size);
   if (!backing_store) {
     // We need to get Webkit to generate a new paint here, as we
     // don't have a previous snapshot.
-    if (bitmap_rect.size() != backing_store_size ||
-        bitmap_rect.x() != 0 || bitmap_rect.y() != 0) {
+    if (paint_rect.size() != backing_store_size ||
+        paint_rect.x() != 0 || paint_rect.y() != 0) {
       DCHECK(needs_full_paint != NULL);
       *needs_full_paint = true;
     }
     backing_store = CreateBackingStore(host, backing_store_size);
   }
 
   DCHECK(backing_store != NULL);
-  backing_store->PaintRect(process_handle, bitmap, bitmap_rect);
+  backing_store->PaintRect(process_handle, bitmap, bitmap_rect, paint_rect);
   return backing_store;
 }
 
 // static
 BackingStore* BackingStoreManager::Lookup(RenderWidgetHost* host) {
   if (cache) {
     BackingStoreCache::iterator it = cache->Peek(host);
     if (it != cache->end())
       return it->second;
   }
   return NULL;
 }
 
 // static
 void BackingStoreManager::RemoveBackingStore(RenderWidgetHost* host) {
   if (!cache)
     return;
 
   BackingStoreCache::iterator it = cache->Peek(host);
   if (it == cache->end())
     return;
 
   cache->Erase(it);
 
   if (cache->empty()) {
     delete cache;
     cache = NULL;
   }
 }