Thumbnails: Add some perf UMA

chrome/browser/thumbnails/thumbnail_tab_helper.cc

Index: chrome/browser/thumbnails/thumbnail_tab_helper.cc
diff --git a/chrome/browser/thumbnails/thumbnail_tab_helper.cc b/chrome/browser/thumbnails/thumbnail_tab_helper.cc
index a60fd56073a0620a8ad744aa6d319d39906591d1..8abfda8859d3150783c4127474e9d685bb720a39 100644
--- a/chrome/browser/thumbnails/thumbnail_tab_helper.cc
+++ b/chrome/browser/thumbnails/thumbnail_tab_helper.cc
@@ -5,7 +5,7 @@
 #include "chrome/browser/thumbnails/thumbnail_tab_helper.h"
 
 #include "base/feature_list.h"
-#include "build/build_config.h"
+#include "base/metrics/histogram_macros.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/thumbnails/thumbnail_service.h"
 #include "chrome/browser/thumbnails/thumbnail_service_factory.h"
@@ -18,7 +18,6 @@
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host.h"
 #include "content/public/browser/render_widget_host_view.h"
-#include "ui/gfx/geometry/size_conversions.h"
 #include "ui/gfx/scrollbar_size.h"
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(ThumbnailTabHelper);
@@ -48,7 +47,7 @@ using content::WebContents;
 using thumbnails::ThumbnailingContext;
 using thumbnails::ThumbnailingAlgorithm;
 
-ThumbnailTabHelper::ThumbnailTabHelper(content::WebContents* contents)

[jochen (gone - plz use gerrit), 2017/05/16 11:15:17]

using content::Something should be the exception, so if you touch that, you
should rather change towards the other direction

[Marc Treib, 2017/05/16 11:48:37]

Done. (For all three "using content::"s)

+ThumbnailTabHelper::ThumbnailTabHelper(WebContents* contents)
     : content::WebContentsObserver(contents),
       capture_on_load_finished_(base::FeatureList::IsEnabled(
           features::kCaptureThumbnailOnLoadFinished)),
@@ -63,8 +62,7 @@ ThumbnailTabHelper::ThumbnailTabHelper(content::WebContents* contents)
                  content::Source<WebContents>(contents));
 }
 
-ThumbnailTabHelper::~ThumbnailTabHelper() {
-}
+ThumbnailTabHelper::~ThumbnailTabHelper() = default;
 
 void ThumbnailTabHelper::Observe(int type,
                                  const content::NotificationSource& source,
@@ -121,12 +119,14 @@ void ThumbnailTabHelper::UpdateThumbnailIfNecessary() {
   // Destroying a WebContents may trigger it to be hidden, prompting a snapshot
   // which would be unwise to attempt <http://crbug.com/130097>. If the
   // WebContents is in the middle of destruction, do not risk it.
-  if (!web_contents() || web_contents()->IsBeingDestroyed())
+  if (!web_contents() || web_contents()->IsBeingDestroyed()) {

[jochen (gone - plz use gerrit), 2017/05/16 11:15:17]

why this change?

if (single line)
  single line;

is already allowed

[Marc Treib, 2017/05/16 11:48:37]

For local consistency, since there are a few other single-line bodies in this
file that do have braces. If you prefer, I can change all of them to not have
braces instead (or just undo these changes - I don't care *that* much).

     return;
+  }
   // Skip if a pending entry exists. WidgetHidden can be called while navigating
   // pages and this is not a time when thumbnails should be generated.
-  if (web_contents()->GetController().GetPendingEntry())
+  if (web_contents()->GetController().GetPendingEntry()) {
     return;
+  }
   const GURL& url = web_contents()->GetURL();
   Profile* profile =
       Profile::FromBrowserContext(web_contents()->GetBrowserContext());
@@ -181,6 +181,7 @@ void ThumbnailTabHelper::AsyncProcessThumbnail(
       scale_factor,
       &copy_rect,
       &thumbnailing_context_->requested_copy_size);
+  copy_from_surface_start_time_ = base::TimeTicks::Now();
   view->CopyFromSurface(copy_rect, thumbnailing_context_->requested_copy_size,
                         base::Bind(&ThumbnailTabHelper::ProcessCapturedBitmap,
                                    weak_factory_.GetWeakPtr(), algorithm),
@@ -191,9 +192,14 @@ void ThumbnailTabHelper::ProcessCapturedBitmap(
     scoped_refptr<ThumbnailingAlgorithm> algorithm,
     const SkBitmap& bitmap,
     content::ReadbackResponse response) {
+  base::TimeDelta copy_from_surface_time =
+      base::TimeTicks::Now() - copy_from_surface_start_time_;
+  UMA_HISTOGRAM_TIMES("Thumbnails.CopyFromSurfaceTime", copy_from_surface_time);
+
   if (response == content::READBACK_SUCCESS) {
     // On success, we must be on the UI thread.
     DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+    process_bitmap_start_time_ = base::TimeTicks::Now();
     algorithm->ProcessBitmap(thumbnailing_context_,
                              base::Bind(&ThumbnailTabHelper::UpdateThumbnail,
                                         weak_factory_.GetWeakPtr()),
@@ -209,14 +215,13 @@ void ThumbnailTabHelper::ProcessCapturedBitmap(
   }
 }
 
-void ThumbnailTabHelper::CleanUpFromThumbnailGeneration() {

[Marc Treib, 2017/05/15 10:16:48]

Moved to match the order in the header.

-  // Make a note that thumbnail generation is complete.
-  thumbnailing_context_ = nullptr;
-}
-
 void ThumbnailTabHelper::UpdateThumbnail(const ThumbnailingContext& context,
                                          const SkBitmap& thumbnail) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  base::TimeDelta process_bitmap_time =
+      base::TimeTicks::Now() - process_bitmap_start_time_;
+  UMA_HISTOGRAM_TIMES("Thumbnails.ProcessBitmapTime", process_bitmap_time);
+
   // Feed the constructed thumbnail to the thumbnail service.
   gfx::Image image = gfx::Image::CreateFrom1xBitmap(thumbnail);
   context.service->SetPageThumbnail(context, image);
@@ -226,6 +231,11 @@ void ThumbnailTabHelper::UpdateThumbnail(const ThumbnailingContext& context,
   CleanUpFromThumbnailGeneration();
 }
 
+void ThumbnailTabHelper::CleanUpFromThumbnailGeneration() {
+  // Make a note that thumbnail generation is complete.
+  thumbnailing_context_ = nullptr;
+}
+
 void ThumbnailTabHelper::RenderViewHostCreated(RenderViewHost* renderer) {
   // NOTIFICATION_WEB_CONTENTS_RENDER_VIEW_HOST_CREATED is really a new
   // RenderView, not RenderViewHost, and there is no good way to get