4 files changed, 17 insertions, 0 deletions
diff --git a/chrome/common/histogram_synchronizer.cc b/chrome/common/histogram_synchronizer.cc
index 2a7e09a..9aeff5e 100644
--- a/chrome/common/histogram_synchronizer.cc
+++ b/chrome/common/histogram_synchronizer.cc
@@ -240,6 +240,9 @@ int HistogramSynchronizer::GetNextAvaibleSequenceNumber(
     RendererHistogramRequester requester) {
   AutoLock auto_lock(lock_);
   ++next_available_sequence_number_;
+  if (0 > next_available_sequence_number_)  // We wrapped around.
+    next_available_sequence_number_ = kReservedSequenceNumber + 1;
+  DCHECK(next_available_sequence_number_ != kReservedSequenceNumber);
   if (requester == ASYNC_HISTOGRAMS) {
     async_sequence_number_ = next_available_sequence_number_;
     async_renderers_pending_ = 0;
diff --git a/chrome/common/histogram_synchronizer.h b/chrome/common/histogram_synchronizer.h
index 35e965e..1190555 100644
--- a/chrome/common/histogram_synchronizer.h
+++ b/chrome/common/histogram_synchronizer.h
@@ -26,6 +26,8 @@ class HistogramSynchronizer : public
     SYNCHRONOUS_HISTOGRAMS
   };
 
+  static const int kReservedSequenceNumber = 0;
+
   HistogramSynchronizer();
 
   ~HistogramSynchronizer();
diff --git a/chrome/renderer/render_view.cc b/chrome/renderer/render_view.cc
index 5c52523..418bf4c 100644
--- a/chrome/renderer/render_view.cc
+++ b/chrome/renderer/render_view.cc
@@ -26,6 +26,7 @@
 #include "chrome/common/child_process_logging.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/chrome_constants.h"
+#include "chrome/common/histogram_synchronizer.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/jstemplate_builder.h"
 #include "chrome/common/page_zoom.h"
@@ -3755,6 +3756,16 @@ void RenderView::DumpLoadHistograms() const {
   }
 
   navigation_state->set_load_histograms_recorded(true);
+
+  // Since there are currently no guarantees that renderer histograms will be
+  // sent to the browser, we initiate a PostTask here to be sure that we send
+  // the histograms we generated.  Without this call, pages that don't have an
+  // on-close-handler might generate data that is lost when the renderer is
+  // shutdown abruptly (perchance because the user closed the tab).
+  if (RenderThread::current()) {
+    RenderThread::current()->SendHistograms(
+        HistogramSynchronizer::kReservedSequenceNumber);
+  }
 }
 
 void RenderView::LogNavigationState(const NavigationState* state,
diff --git a/chrome/renderer/renderer_histogram_snapshots.cc b/chrome/renderer/renderer_histogram_snapshots.cc
index 025eb73..5b8165a 100644
--- a/chrome/renderer/renderer_histogram_snapshots.cc
+++ b/chrome/renderer/renderer_histogram_snapshots.cc
@@ -37,6 +37,7 @@ void RendererHistogramSnapshots::UploadAllHistrograms(int sequence_number) {
   for (StatisticsRecorder::Histograms::iterator it = histograms.begin();
        histograms.end() != it;
        it++) {
+    (*it)->SetFlags(Histogram::kIPCSerializationSourceFlag);
     UploadHistrogram(**it, &pickled_histograms);
   }
   // Send the sequence number and list of pickled histograms over synchronous