Native memory histograms for the browser.

content/common/child_process_messages.h

 // Copyright (c) 2012 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.
 
 // Common IPC messages used for child processes.
 // Multiply-included message file, hence no include guard.
 
 #include <string>
 #include <vector>
 
@@ skipping 90 matching lines @@
 // Send back profiler data (ThreadData in tracked_objects).
 IPC_MESSAGE_CONTROL2(ChildProcessHostMsg_ChildProfilerData,
                      int, /* sequence_number */
                      tracked_objects::ProcessDataSnapshot /* profiler_data */)
 
 // Send back histograms as vector of pickled-histogram strings.
 IPC_MESSAGE_CONTROL2(ChildProcessHostMsg_ChildHistogramData,
                      int, /* sequence_number */
                      std::vector<std::string> /* histogram_data */)
 
+// Request a histogram from the browser.

[Charlie Reis, 2013/01/22 23:31:31]

nit: Please mention that this is only available behind the memory metrics flag
here (since I had the same concern as Tom about leaking data if that ever
changed).

[marja, 2013/01/23 08:28:44]

Done.

+IPC_SYNC_MESSAGE_CONTROL1_1(ChildProcessHostMsg_GetBrowserHistogram,
+                            std::string, /* histogram_name */
+                            std::string /* histogram_json */)
+
 // Reply to ChildProcessMsg_DumpHandles when handle table dump is complete.
 IPC_MESSAGE_CONTROL0(ChildProcessHostMsg_DumpHandlesDone)
 
 #if defined(OS_WIN)
 // Request that the given font be loaded by the host so it's cached by the
 // OS. Please see ChildProcessHost::PreCacheFont for details.
 IPC_SYNC_MESSAGE_CONTROL1_0(ChildProcessHostMsg_PreCacheFont,
                             LOGFONT /* font data */)
 
 // Release the cached font
 IPC_MESSAGE_CONTROL0(ChildProcessHostMsg_ReleaseCachedFonts)
 #endif  // defined(OS_WIN)
 
 // Asks the browser to create a block of shared memory for the child process to
 // fill in and pass back to the browser.
 IPC_SYNC_MESSAGE_CONTROL1_1(ChildProcessHostMsg_SyncAllocateSharedMemory,
                             uint32 /* buffer size */,
                             base::SharedMemoryHandle)
 
 #if defined(USE_TCMALLOC)
 // Reply to ChildProcessMsg_GetTcmallocStats.
 IPC_MESSAGE_CONTROL1(ChildProcessHostMsg_TcmallocStats,
                      std::string /* output */)
 #endif