Add trace events for renderer thumbnailer, it can be quite expensive

chrome/renderer/chrome_render_view_observer.cc

 // Copyright (c) 2011 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/renderer/chrome_render_view_observer.h"
 
 #include "base/command_line.h"
+#include "base/debug/trace_event.h"
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/icon_messages.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/common/thumbnail_score.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/renderer/about_handler.h"
@@ skipping 813 matching lines @@
   // reload, in-page navigation, or some other load type where we don't want to
   // reindex.  Note: subframe navigations after onload increment the page id,
   // so these will trigger a reindex.
   GURL stripped_url(StripRef(url));
   if (same_page_id && stripped_url == last_indexed_url_)
     return;
 
   if (!preliminary_capture)
     last_indexed_url_ = stripped_url;
 
+  TRACE_EVENT0("renderer", "ChromeRenderViewObserver::CapturePageInfo");
+
   // Retrieve the frame's full text.
   string16 contents;
   CaptureText(main_frame, &contents);
   if (translate_helper_)
     translate_helper_->PageCaptured(contents);
   if (contents.size()) {
     // Send the text to the browser for indexing (the browser might decide not
     // to index, if the URL is HTTPS for instance) and language discovery.
     Send(new ChromeViewHostMsg_PageContents(routing_id(), url, load_id,
                                             contents));
@@ skipping 51 matching lines @@
     return;
 
   // get the URL for this page
   GURL url(main_frame->document().url());
   if (url.is_empty())
     return;
 
   if (render_view()->GetSize().IsEmpty())
     return;  // Don't create an empty thumbnail!
 
+  TRACE_EVENT0("renderer", "ChromeRenderViewObserver::CaptureThumbnail");
+
   ThumbnailScore score;
   SkBitmap thumbnail;
   if (!CaptureFrameThumbnail(render_view()->GetWebView(), kThumbnailWidth,
                              kThumbnailHeight, &thumbnail, &score))
     return;
 
   // send the thumbnail message to the browser process
   Send(new ChromeViewHostMsg_Thumbnail(routing_id(), url, score, thumbnail));
 }
 
 bool ChromeRenderViewObserver::CaptureFrameThumbnail(WebView* view,
                                                      int w,
                                                      int h,
                                                      SkBitmap* thumbnail,
                                                      ThumbnailScore* score) {
   base::TimeTicks beginning_time = base::TimeTicks::Now();
 
   skia::PlatformCanvas canvas;
 
-  // Paint |view| into |canvas|.
-  if (!PaintViewIntoCanvas(view, canvas))
-    return false;
+  {
+    TRACE_EVENT0("renderer",
+        "ChromeRenderViewObserver::CaptureFrameThumbnail::PaintViewIntoCanvas");
+    // Paint |view| into |canvas|.
+    if (!PaintViewIntoCanvas(view, canvas))
+      return false;
+  }
 
   SkDevice* device = skia::GetTopDevice(canvas);
 
   const SkBitmap& src_bmp = device->accessBitmap(false);
   // Cut off the vertical scrollbars (if any).
   int src_bmp_width = view->mainFrame()->contentsSize().width;
 
   SkRect dest_rect = { 0, 0, SkIntToScalar(w), SkIntToScalar(h) };
   float dest_aspect = dest_rect.width() / dest_rect.height();
 
@@ skipping 22 matching lines @@
                    static_cast<S16CPU>(src_bmp_width / dest_aspect));
       score->good_clipping = true;
     }
   }
 
   score->at_top = (view->mainFrame()->scrollOffset().height == 0);
 
   SkBitmap subset;
   device->accessBitmap(false).extractSubset(&subset, src_rect);
 
+  TRACE_EVENT_BEGIN0("renderer",
+        "ChromeRenderViewObserver::CaptureFrameThumbnail::DownsampleByTwo");
   // First do a fast downsample by powers of two to get close to the final size.
   SkBitmap downsampled_subset =
       SkBitmapOperations::DownsampleByTwoUntilSize(subset, w, h);
+  TRACE_EVENT_END0("renderer",
+        "ChromeRenderViewObserver::CaptureFrameThumbnail::DownsampleByTwo");
 
-  // Do a high-quality resize from the downscaled size to the final size.
-  *thumbnail = skia::ImageOperations::Resize(
-      downsampled_subset, skia::ImageOperations::RESIZE_LANCZOS3, w, h);
+  {
+    TRACE_EVENT0("renderer",
+        "ChromeRenderViewObserver::CaptureFrameThumbnail::DownsampleLanczos3");
+    // Do a high-quality resize from the downscaled size to the final size.
+    *thumbnail = skia::ImageOperations::Resize(
+        downsampled_subset, skia::ImageOperations::RESIZE_LANCZOS3, w, h);
+  }
 
   score->boring_score = CalculateBoringScore(thumbnail);
 
   HISTOGRAM_TIMES("Renderer4.Thumbnail",
                   base::TimeTicks::Now() - beginning_time);
 
   return true;
 }
 
 bool ChromeRenderViewObserver::CaptureSnapshot(WebView* view,
@@ skipping 76 matching lines @@
     // Decode the favicon using WebKit's image decoder.
     webkit_glue::ImageDecoder decoder(
         gfx::Size(gfx::kFaviconSize, gfx::kFaviconSize));
     const unsigned char* src_data =
         reinterpret_cast<const unsigned char*>(&data[0]);
 
     return decoder.Decode(src_data, data.size());
   }
   return SkBitmap();
 }