Prepare for per frame did{Start,Stop}Loading calls

content/renderer/load_progress_tracker.cc

Index: content/renderer/load_progress_tracker.cc
diff --git a/content/renderer/load_progress_tracker.cc b/content/renderer/load_progress_tracker.cc
index 0cc26fdcccf14ef4ac74b52f9ea36d252fe85d91..05c3ed6675e05af2d886a0e9e75f7f6c612b14ad 100644
--- a/content/renderer/load_progress_tracker.cc
+++ b/content/renderer/load_progress_tracker.cc
@@ -14,39 +14,42 @@ namespace {
 
 const int kMinimumDelayBetweenUpdatesMS = 100;
 
+// This matches what blink's ProgrssTracker has traditionally used for a
+// minmum progress value.

[Charlie Reis, 2014/03/11 21:51:12]

nit: minimum

+const double kMinimumProgress = 0.1;
+
 }
 
 LoadProgressTracker::LoadProgressTracker(RenderViewImpl* render_view)
     : render_view_(render_view),
-      tracked_frame_(NULL),
-      progress_(0.0),
+      total_progress_(0.0),
       weak_factory_(this) {
 }
 
 LoadProgressTracker::~LoadProgressTracker() {
 }
 
-void LoadProgressTracker::DidStopLoading() {
-  if (!tracked_frame_)
+void LoadProgressTracker::DidStartLoading(int frame_routing_id) {
+  progresses_[frame_routing_id] = kMinimumProgress;
+  SendChangeLoadProgress();
+}
+
+void LoadProgressTracker::DidStopLoading(int frame_routing_id) {
+  if (progresses_.find(frame_routing_id) == progresses_.end())
     return;
 
-  // Load stopped while we were still tracking load.  Make sure we notify the
-  // browser that load is complete.
-  progress_ = 1.0;
+  // Load stopped while we were still tracking load.  Make sure we update
+  // progress based on this frame's completion.
+  progresses_[frame_routing_id] = 1.0;
   SendChangeLoadProgress();
   // Then we clean-up our states.
-  ResetStates();
+  if (total_progress_ == 1.0)
+    ResetStates();
 }
 
-void LoadProgressTracker::DidChangeLoadProgress(blink::WebFrame* frame,
+void LoadProgressTracker::DidChangeLoadProgress(int frame_routing_id,
                                                 double progress) {
-  if (tracked_frame_ && frame != tracked_frame_)
-    return;
-
-  if (!tracked_frame_)
-    tracked_frame_ = frame;
-
-  progress_ = progress;
+  progresses_[frame_routing_id] = progress;
 
   // We send the progress change to the browser immediately for the first and
   // last updates.  Also, since the message loop may be pretty busy when a page
@@ -60,7 +63,7 @@ void LoadProgressTracker::DidChangeLoadProgress(blink::WebFrame* frame,
     // If there is a pending task to send progress, it is now obsolete.
     weak_factory_.InvalidateWeakPtrs();
     SendChangeLoadProgress();
-    if (progress == 1.0)
+    if (total_progress_ == 1.0)
       ResetStates();
     return;
   }
@@ -77,14 +80,28 @@ void LoadProgressTracker::DidChangeLoadProgress(blink::WebFrame* frame,
 
 void LoadProgressTracker::SendChangeLoadProgress() {
   last_time_progress_sent_ = base::TimeTicks::Now();
+  double progress = 0.0;
+  unsigned frameCount = 0;
+  ProgressMap::iterator end = progresses_.end();
+  for (ProgressMap::iterator it = progresses_.begin(); it != end; ++it) {
+    progress += it->second;
+    frameCount++;
+  }
+  progress /= frameCount;

[Charlie Reis, 2014/03/11 21:51:12]

This is crying out to divide by zero if progresses_ is ever empty.  :)

[Nate Chapin, 2014/03/11 22:09:59]

That shouldn't be possible, but...yeah, let's just add an early exit.

+  DCHECK(progress <= 1.0);
+
+  if (progress <= total_progress_)
+    return;
+  total_progress_ = progress;
+
   render_view_->Send(
       new ViewHostMsg_DidChangeLoadProgress(render_view_->routing_id(),
-                                            progress_));
+                                            progress));
 }
 
 void LoadProgressTracker::ResetStates() {
-  tracked_frame_ = NULL;
-  progress_ = 0.0;
+  progresses_.clear();
+  total_progress_ = 0.0;
   weak_factory_.InvalidateWeakPtrs();
   last_time_progress_sent_ = base::TimeTicks();
 }