fix multibuffer "is loading"

media/blink/multibuffer_data_source.cc

 // Copyright 2013 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.
 
 #include "media/blink/multibuffer_data_source.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
@@ skipping 487 matching lines @@
     media_log_->SetBooleanProperty("single_origin", single_origin_);
     media_log_->SetBooleanProperty("passed_cors_access_check",
                                    DidPassCORSAccessCheck());
     media_log_->SetBooleanProperty("range_header_supported",
                                    url_data_->range_supported());
   }
 
   render_task_runner_->PostTask(
       FROM_HERE, base::Bind(base::ResetAndReturn(&init_cb_), success));
 
+  // When we tell our clients that we're loading below, it's possible that
+  // the entire file is already cashed. If that's true, then we won't get
+  // any progress callbacks later, so we'll never tell the client that we
+  // stopped loading. Post a task to make sure that we check the loading
+  // state at least once.
+  render_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&MultibufferDataSource::UpdateLoadingState,
+                            weak_factory_.GetWeakPtr()));
   // Even if data is cached, say that we're loading at this point for
   // compatibility.
   UpdateLoadingState_Locked(true);
 }
 
 void MultibufferDataSource::ProgressCallback(int64_t begin, int64_t end) {
   DVLOG(1) << __func__ << "(" << begin << ", " << end << ")";
   DCHECK(render_task_runner_->BelongsToCurrentThread());
 
   if (assume_fully_buffered())
@@ skipping 27 matching lines @@
 
     if (!loading_ && cancel_on_defer_) {
       reader_.reset(nullptr);
     }
 
     // Callback could kill us, be sure to call it last.
     downloading_cb_.Run(loading_);
   }
 }
 
+void MultibufferDataSource::UpdateLoadingState() {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+  base::AutoLock auto_lock(lock_);
+  UpdateLoadingState_Locked(false);
+}
+
 void MultibufferDataSource::UpdateBufferSizes() {
   DVLOG(1) << __func__;
   if (!reader_)
     return;
 
   if (!assume_fully_buffered()) {
     // If the playback has started and the strategy is aggressive, then try to
     // load as much as possible, assuming that the file is cacheable. (If not,
     // why bother?)
     bool aggressive = (buffering_strategy_ == BUFFERING_STRATEGY_AGGRESSIVE);
@@ skipping 36 matching lines @@
   reader_->SetPinRange(back_buffer, kMaxBufferPreload + kPreloadHighExtra);
 
   if (preload_ == METADATA) {
     reader_->SetPreload(0, 0);
   } else {
     reader_->SetPreload(preload_high, preload);
   }
 }
 
 }  // namespace media