make multibuffer work with layout tests

media/blink/multibuffer_data_source.cc

Index: media/blink/multibuffer_data_source.cc
diff --git a/media/blink/multibuffer_data_source.cc b/media/blink/multibuffer_data_source.cc
index 1b01b0813df5ce8d731fb2ee48af6543a8c347c6..e400035fb42b8cfad7e71b5fce584203038b85cb 100644
--- a/media/blink/multibuffer_data_source.cc
+++ b/media/blink/multibuffer_data_source.cc
@@ -175,7 +175,6 @@ void MultibufferDataSource::Initialize(const InitializeCB& init_cb) {
     reader_->Wait(1,
                   base::Bind(&MultibufferDataSource::StartCallback, weak_ptr_));
   }
-  UpdateLoadingState();
 }
 
 void MultibufferDataSource::OnRedirect(
@@ -229,6 +228,7 @@ void MultibufferDataSource::OnRedirect(
 }
 
 void MultibufferDataSource::SetPreload(Preload preload) {
+  DVLOG(1) << __FUNCTION__ << "(" << preload << ")";
   DCHECK(render_task_runner_->BelongsToCurrentThread());
   preload_ = preload;
   UpdateBufferSizes();
@@ -392,7 +392,7 @@ void MultibufferDataSource::ReadTask() {
   } else {
     reader_->Wait(1, base::Bind(&MultibufferDataSource::ReadTask,
                                 weak_factory_.GetWeakPtr()));
-    UpdateLoadingState();
+    UpdateLoadingState(false);
   }
 }
 
@@ -475,12 +475,16 @@ void MultibufferDataSource::StartCallback() {
                                    url_data_->range_supported());
   }
 
-  UpdateLoadingState();
   render_task_runner_->PostTask(
       FROM_HERE, base::Bind(base::ResetAndReturn(&init_cb_), success));
+
+  // Even if data is cached, say that we're loading at this point for
+  // compatibility.
+  UpdateLoadingState(true);
 }
 
 void MultibufferDataSource::ProgressCallback(int64 begin, int64 end) {
+  DVLOG(1) << __FUNCTION__ << "(" << begin << ", " << end << ")";
   DCHECK(render_task_runner_->BelongsToCurrentThread());
 
   if (assume_fully_buffered())
@@ -496,13 +500,17 @@ void MultibufferDataSource::ProgressCallback(int64 begin, int64 end) {
     host_->AddBufferedByteRange(begin, end);
   }
 
-  UpdateLoadingState();
+  UpdateLoadingState(false);
 }
 
-void MultibufferDataSource::UpdateLoadingState() {
+void MultibufferDataSource::UpdateLoadingState(bool force_loading) {
+  DVLOG(1) << __FUNCTION__;
+  if (assume_fully_buffered())
+    return;
   // Update loading state.
-  if ((!!reader_ && reader_->IsLoading()) != loading_) {
-    loading_ = !loading_;
+  bool is_loading = !!reader_ && reader_->IsLoading();
+  if (force_loading || is_loading != loading_) {
+    loading_ = is_loading || force_loading;

[liberato (no reviews please), 2015/12/08 21:59:33]

if the reader reports !loading, how does loading_ get cleared here if we force
it to be set here?

in other words, what happens if we just call |downloading_cb_|(true) without
setting |loading_|?

[hubbe, 2015/12/08 22:25:59]

Updated comment for |loading_|.
loading_ will be set to the true value next time UpdateLoadingState() is called.

 
     if (!loading_ && cancel_on_defer_) {

[liberato (no reviews please), 2015/12/08 21:59:33]

this can happen on force_loading that wouldn't have happened before, since
loading_ defaults to false, and the if at 512 wouldn't get us here.  is that
intentional?

[hubbe, 2015/12/08 22:25:59]

if force_loading is true, then loading_ will be true and this cannot happen.

       reader_.reset(nullptr);
@@ -514,6 +522,7 @@ void MultibufferDataSource::UpdateLoadingState() {
 }
 
 void MultibufferDataSource::UpdateBufferSizes() {
+  DVLOG(1) << __FUNCTION__;
   if (!reader_)
     return;