Flush stability file after initialization

chrome/browser/chrome_browser_field_trials_desktop.cc

Index: chrome/browser/chrome_browser_field_trials_desktop.cc
diff --git a/chrome/browser/chrome_browser_field_trials_desktop.cc b/chrome/browser/chrome_browser_field_trials_desktop.cc
index 47715a06258dff1e92f36cdbb9c33c3b44687a00..e61c1fdb1e99607b5703e681eec2db9f281dd56e 100644
--- a/chrome/browser/chrome_browser_field_trials_desktop.cc
+++ b/chrome/browser/chrome_browser_field_trials_desktop.cc
@@ -175,6 +175,13 @@ void SetupStabilityDebugging() {
 
     // Record information about chrome's module. We want this to be done early.
     RecordChromeModuleInfo(global_tracker);
+
+    // Trigger a flush of the memory mapped file to maximize the chances of
+    // having a minimal amount of content in the stability file, even if
+    // the system crashes or loses power. Note: this does not flush the file
+    // metadata nor does it wait for the changes to be flushed to disk before
+    // returning.
+    ::FlushViewOfFile(global_tracker->allocator()->data(), 0U);

[bcwhite, 2017/03/06 13:59:17]

How about making this a method off of GlobalActivityTracker so it can be
cross-platform and reusable.

Perhaps with a boolean "synchronous" flag that waits for the flush?

[manzagop (departed), 2017/03/06 16:46:26]

I guess GlobalActivityTracker would have a flush that calls to the allocator's
flush that only has an effect if it's a FilePersistentMemoryAllocator? And the
actual flushing would be in base::MemoryMappedFile?

If you agree, maybe we can start with this and in parallel, have another CL to
add flushing to base::MemoryMappedFile?

[bcwhite, 2017/03/07 18:37:26]

Yeah...  It would have to be a virtual method on the PMA.  Best to do that in a
different CL.  I'll look into it.

   }
 }
 #endif  // defined(OS_WIN)