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

content/common/discardable_shared_memory_heap.cc

 // 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.
 
 #include "content/common/discardable_shared_memory_heap.h"
 
 #include "base/memory/discardable_shared_memory.h"
 
 namespace content {
 namespace {
@@ skipping 124 matching lines @@
       if ((span->length_ == best->length_) && (span->start_ > best->start_))
         continue;
     }
 
     best = span;
   }
 
   return best ? Carve(best, blocks) : nullptr;
 }
 
-void DiscardableSharedMemoryHeap::ReleaseFreeMemory() {
+size_t DiscardableSharedMemoryHeap::ReleaseFreeMemory() {
+  size_t bytes_released = 0;
   size_t i = 0;
 
   // Release memory for all non-resident segments.
   while (i < shared_memory_segments_.size()) {
     base::DiscardableSharedMemory* shared_memory = shared_memory_segments_[i];
 
     // Skip segment if still resident.
     if (shared_memory->IsMemoryResident()) {
       ++i;
       continue;
     }
 
+    bytes_released += shared_memory->mapped_size();
+
     // Release the memory and unregistering all associated spans.
     ReleaseMemory(shared_memory);
 
     std::swap(shared_memory_segments_[i], shared_memory_segments_.back());
     shared_memory_segments_.pop_back();
   }
+
+  return bytes_released;
 }
 
 scoped_ptr<DiscardableSharedMemoryHeap::Span>
 DiscardableSharedMemoryHeap::RemoveFromFreeList(Span* span) {
   span->RemoveFromList();
   return make_scoped_ptr(span);
 }
 
 scoped_ptr<DiscardableSharedMemoryHeap::Span>
 DiscardableSharedMemoryHeap::Carve(Span* span, size_t blocks) {
@@ skipping 49 matching lines @@
 
     offset += span->length_;
 
     // If |span| is in the free list, remove it.
     if (IsInFreeList(span))
       RemoveFromFreeList(span);
   }
 }
 
 }  // namespace content