Add TopSites::GetTemporaryThumbnailScore().

This will make the in-browser thumbnailing more efficient. Before this
change, we regenerated a thumbnail even when we had a good thumbnail,
if it's not yet saved (this occurred when the top site list was not yet full)

BUG=65936
TEST=confirm that the in-browser thumbnailing doesn't regenerate a thumbnail when we already have one.

Review URL: http://codereview.chromium.org/6813040

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@81216 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 31 insertions, 4 deletions

diff --git a/chrome/browser/history/top_sites.cc b/chrome/browser/history/top_sites.cc
index 71d3316..d1ea4a4 100644
--- a/chrome/browser/history/top_sites.cc
+++ b/chrome/browser/history/top_sites.cc
@@ -257,6 +257,19 @@ bool TopSites::GetPageThumbnailScore(const GURL& url,
   return thread_safe_cache_->GetPageThumbnailScore(url, score);
 }
 
+bool TopSites::GetTemporaryPageThumbnailScore(const GURL& url,
+                                              ThumbnailScore* score) {
+  for (TempImages::iterator i = temp_images_.begin(); i != temp_images_.end();
+       ++i) {
+    if (i->first == url) {
+      *score = i->second.thumbnail_score;
+      return true;
+    }
+  }
+  return false;
+}
+
+
 // Returns the index of |url| in |urls|, or -1 if not found.
 static int IndexOf(const MostVisitedURLList& urls, const GURL& url) {
   for (size_t i = 0; i < urls.size(); i++) {
diff --git a/chrome/browser/history/top_sites.h b/chrome/browser/history/top_sites.h
index 3e20488..bfe78cb 100644
--- a/chrome/browser/history/top_sites.h
+++ b/chrome/browser/history/top_sites.h
@@ -84,6 +84,11 @@ class TopSites
   // be copied to |score|.
   virtual bool GetPageThumbnailScore(const GURL& url, ThumbnailScore* score);
 
+  // Get a temporary thumbnail score for a given page. Returns true iff we
+  // have the thumbnail score. Useful when checking if we should update a
+  // thumbnail for a given page. The score will be copied to |score|.
+  bool GetTemporaryPageThumbnailScore(const GURL& url, ThumbnailScore* score);
+
   // Invoked from History if migration is needed. If this is invoked it will
   // be before HistoryLoaded is invoked.
   void MigrateFromHistory();
diff --git a/chrome/browser/history/top_sites_unittest.cc b/chrome/browser/history/top_sites_unittest.cc
index a806b8d..c197231 100644
--- a/chrome/browser/history/top_sites_unittest.cc
+++ b/chrome/browser/history/top_sites_unittest.cc
@@ -1098,6 +1098,11 @@ TEST_F(TopSitesTest, AddTemporaryThumbnail) {
   // We shouldn't get the thumnail back though (the url isn't in to sites yet).
   scoped_refptr<RefCountedBytes> out;
   EXPECT_FALSE(top_sites()->GetPageThumbnail(unknown_url, &out));
+  // But we should be able to get the temporary page thumbnail score.
+  ThumbnailScore out_score;
+  EXPECT_TRUE(top_sites()->GetTemporaryPageThumbnailScore(unknown_url,
+                                                          &out_score));
+  EXPECT_TRUE(medium_score.Equals(out_score));
 
   std::vector<MostVisitedURL> list;
 
diff --git a/chrome/browser/tab_contents/thumbnail_generator.cc b/chrome/browser/tab_contents/thumbnail_generator.cc
index 6acae58..f9c2d58 100644
--- a/chrome/browser/tab_contents/thumbnail_generator.cc
+++ b/chrome/browser/tab_contents/thumbnail_generator.cc
@@ -671,15 +671,19 @@ bool ThumbnailGenerator::ShouldUpdateThumbnail(Profile* profile,
   if (!HistoryService::CanAddURL(url))
     return false;
   // Skip if the top sites list is full, and the URL is not known.
-  const bool is_known = top_sites->IsKnownURL(url);
-  if (top_sites->IsFull() && !is_known)
+  if (top_sites->IsFull() && !top_sites->IsKnownURL(url))
     return false;
   // Skip if we don't have to udpate the existing thumbnail.
   ThumbnailScore current_score;
-  if (is_known &&
-      top_sites->GetPageThumbnailScore(url, &current_score) &&
+  if (top_sites->GetPageThumbnailScore(url, &current_score) &&
       !current_score.ShouldConsiderUpdating())
     return false;
+  // Skip if we don't have to udpate the temporary thumbnail (i.e. the one
+  // not yet saved).
+  ThumbnailScore temporary_score;
+  if (top_sites->GetTemporaryPageThumbnailScore(url, &temporary_score) &&
+      !temporary_score.ShouldConsiderUpdating())
+    return false;
 
   return true;
 }