content: Update crash key and discardable memory usage counter in child process.

content/common/discardable_shared_memory_heap.h

 // Copyright 2014 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.
 
 #ifndef CONTENT_COMMON_DISCARDABLE_SHARED_MEMORY_HEAP_H_
 #define CONTENT_COMMON_DISCARDABLE_SHARED_MEMORY_HEAP_H_
 
 #include <bitset>
 
 #include "base/containers/hash_tables.h"
@@ skipping 50 matching lines @@
 
   // Split an allocated span into two spans, one of length |blocks| followed
   // by another span of length "span->length - blocks" blocks. Modifies |span|
   // to point to the first span of length |blocks|. Return second span.
   scoped_ptr<Span> Split(Span* span, size_t blocks);
 
   // Search free list for span that satisfies the request for |blocks| of
   // memory. If found, the span is removed from the free list and returned.
   scoped_ptr<Span> SearchFreeList(size_t blocks);
 
-  // Release shared memory segments that have been purged.
-  void ReleaseFreeMemory();
+  // Release shared memory segments that have been purged. Returns bytes of
+  // memory that were released.
+  size_t ReleaseFreeMemory();
 
  private:
   scoped_ptr<Span> RemoveFromFreeList(Span* span);
   scoped_ptr<Span> Carve(Span* span, size_t blocks);
   void RegisterSpan(Span* span);
   void UnregisterSpan(Span* span);
   void ReleaseMemory(base::DiscardableSharedMemory* shared_memory);
 
   size_t block_size_;
 
   // Discardable shared memory instances.
   ScopedVector<base::DiscardableSharedMemory> shared_memory_segments_;
 
   // Mapping from first/last block of span to Span instance.
   typedef base::hash_map<size_t, Span*> SpanMap;
   SpanMap spans_;
 
   // Linked-list of free discardable memory regions.
   base::LinkedList<Span> free_spans_;
 
   DISALLOW_COPY_AND_ASSIGN(DiscardableSharedMemoryHeap);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_DISCARDABLE_SHARED_MEMORY_HEAP_H_