Add common page filtering logic for page load metrics.

chrome/browser/page_load_metrics/metrics_web_contents_observer.cc

Index: chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
diff --git a/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc b/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
index 86a76e25c8ed3f35079a4c580c73489dbca8cff0..cd71a94875b29899f47dfe4112b9330b0fabdfa9 100644
--- a/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
+++ b/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
@@ -14,6 +14,7 @@
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/user_metrics.h"
+#include "chrome/browser/page_load_metrics/browser_page_track_decider.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_util.h"
 #include "chrome/common/page_load_metrics/page_load_metrics_messages.h"
 #include "chrome/common/page_load_metrics/page_load_timing.h"
@@ -27,6 +28,7 @@
 #include "content/public/browser/web_contents_user_data.h"
 #include "ipc/ipc_message.h"
 #include "ipc/ipc_message_macros.h"
+#include "net/http/http_response_headers.h"
 #include "ui/base/page_transition_types.h"
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(
@@ -1061,18 +1063,13 @@ void MetricsWebContentsObserver::OnTimingUpdated(
 bool MetricsWebContentsObserver::ShouldTrackNavigation(
     content::NavigationHandle* navigation_handle) const {
   DCHECK(navigation_handle->IsInMainFrame());
-  if (!navigation_handle->GetURL().SchemeIsHTTPOrHTTPS())
-    return false;
-  if (embedder_interface_->IsNewTabPageUrl(navigation_handle->GetURL()))
+
+  // Ignore same-page navigations.
+  if (navigation_handle->HasCommitted() && navigation_handle->IsSamePage())

[Charlie Harrison, 2016/09/14 13:20:05]

Why can't this go into the tracker?

[Bryan McQuade, 2016/09/14 15:10:58]

Good question. I decided that the concept of a same page navigation isn't an
attribute of a page load, but rather is a detail specific to navigation.

Similarly to how we bail early for non-main-frame navigations, I updated the
logic to also bail early for same page navigations. This is consistent with our
bail early logic in the render process.

I think this is better overall - same page navs aren't (currently) interesting
to us and I think we want to ignore them and bail early before we even get into
deciding if we should track the page load. See what you think.

[Charlie Harrison, 2016/09/14 16:27:32]

Great explanation, I just wonder if we want to be explicit about also blocking
these in the renderer (I'm not entirely sure how that process works today).

[Bryan McQuade, 2016/09/15 22:28:10]

Sure, we have code in place in the renderer to block these:

void MetricsRenderFrameObserver::DidCommitProvisionalLoad(
    bool is_new_navigation,
    bool is_same_page_navigation) {
  if (is_same_page_navigation)
    return;

  page_timing_metrics_sender_.reset();

  if (ShouldSendMetrics()) {
...

     return false;
-  if (navigation_handle->HasCommitted()) {
-    if (navigation_handle->IsSamePage() || navigation_handle->IsErrorPage())
-      return false;
-    const std::string& mime_type = web_contents()->GetContentsMimeType();
-    if (mime_type != "text/html" && mime_type != "application/xhtml+xml")
-      return false;
-  }
-  return true;
+
+  return BrowserPageTrackDecider(embedder_interface_.get(), web_contents(),
+                                 navigation_handle).ShouldTrack();
 }
 
 }  // namespace page_load_metrics