[page_load_metrics] Add support for chrome:// urls and add extensions observer

chrome/browser/page_load_metrics/metrics_web_contents_observer.cc

 // Copyright 2015 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 "chrome/browser/page_load_metrics/metrics_web_contents_observer.h"
 
 #include <algorithm>
 #include <ostream>
 #include <string>
 #include <utility>
@@ skipping 285 matching lines @@
       started_in_foreground_(in_foreground),
       page_transition_(navigation_handle->GetPageTransition()),
       num_cache_requests_(0),
       num_network_requests_(0),
       user_gesture_(IsNavigationUserInitiated(navigation_handle)),
       aborted_chain_size_(aborted_chain_size),
       aborted_chain_size_same_url_(aborted_chain_size_same_url),
       embedder_interface_(embedder_interface) {
   DCHECK(!navigation_handle->HasCommitted());
   embedder_interface_->RegisterObservers(this);
+
+  FilterObservers(navigation_handle);
   for (const auto& observer : observers_) {
     observer->OnStart(navigation_handle, currently_committed_url,
                       started_in_foreground_);
   }
 }
 
 PageLoadTracker::~PageLoadTracker() {
   if (app_entered_background_) {
     RecordAppBackgroundPageLoadCompleted(true);
   }
@@ skipping 71 matching lines @@
                            aborted_chain_size_);
       return;
     default:
       NOTREACHED()
           << "LogAbortChainHistograms received unexpected ui::PageTransition: "
           << committed_transition;
       return;
   }
 }
 
+void PageLoadTracker::FilterObservers(
+    content::NavigationHandle* navigation_handle) {
+  auto it = observers_.begin();
+  while (it != observers_.end()) {
+    if ((*it)->ShouldTrackLoad(navigation_handle) == IGNORE) {
+      it = observers_.erase(it);
+    } else {
+      ++it;
+    }
+  }
+}
+
 void PageLoadTracker::WebContentsHidden() {
   // Only log the first time we background in a given page load.
   if (background_time_.is_null()) {
     // Make sure we either started in the foreground and haven't been
     // foregrounded yet, or started in the background and have already been
     // foregrounded.
     DCHECK_EQ(started_in_foreground_, foreground_time_.is_null());
     background_time_ = base::TimeTicks::Now();
     ClampBrowserTimestampIfInterProcessTimeTickSkew(&background_time_);
   }
@@ skipping 19 matching lines @@
 
 void PageLoadTracker::Commit(content::NavigationHandle* navigation_handle) {
   // TODO(bmcquade): To improve accuracy, consider adding commit time to
   // NavigationHandle. Taking a timestamp here should be close enough for now.
   commit_time_ = base::TimeTicks::Now();
   ClampBrowserTimestampIfInterProcessTimeTickSkew(&commit_time_);
   url_ = navigation_handle->GetURL();
   // Some transitions (like CLIENT_REDIRECT) are only known at commit time.
   page_transition_ = navigation_handle->GetPageTransition();
   user_gesture_ = navigation_handle->HasUserGesture();
+
+  FilterObservers(navigation_handle);
   for (const auto& observer : observers_) {
     observer->OnCommit(navigation_handle);
   }
   LogAbortChainHistograms(navigation_handle);
 }
 
 void PageLoadTracker::FailedProvisionalLoad(
     content::NavigationHandle* navigation_handle) {
   DCHECK(!failed_provisional_load_info_);
   failed_provisional_load_info_.reset(new FailedProvisionalLoadInfo(
@@ skipping 596 matching lines @@
   // While timings arriving for the wrong frame are expected, we do not expect
   // any of the errors below. Thus, we track occurrences of all errors below,
   // rather than returning early after encountering an error.
 
   bool error = false;
   if (!committed_load_) {
     RecordInternalError(ERR_IPC_WITH_NO_RELEVANT_LOAD);
     error = true;
   }
 
-  if (!web_contents()->GetLastCommittedURL().SchemeIsHTTPOrHTTPS()) {
-    RecordInternalError(ERR_IPC_FROM_BAD_URL_SCHEME);
-    error = true;
-  }
-
   if (error)
     return;
 
   if (!committed_load_->UpdateTiming(timing, metadata)) {
     // If the page load tracker cannot update its timing, something is wrong
     // with the IPC (it's from another load, or it's invalid in some other way).
     // We expect this to be a rare occurrence.
     RecordInternalError(ERR_BAD_TIMING_IPC);
   }
 }
 
 bool MetricsWebContentsObserver::ShouldTrackNavigation(
     content::NavigationHandle* navigation_handle) const {
   DCHECK(navigation_handle->IsInMainFrame());
   DCHECK(!navigation_handle->HasCommitted() ||
          !navigation_handle->IsSamePage());
 
   return BrowserPageTrackDecider(embedder_interface_.get(), web_contents(),
                                  navigation_handle).ShouldTrack();
 }
 
 }  // namespace page_load_metrics