Prevent browser thumbnailer from trying to read from frontbuffer (surface texture) when none exists.

chrome/browser/tab_contents/thumbnail_generator_unittest.cc

Index: chrome/browser/tab_contents/thumbnail_generator_unittest.cc
diff --git a/chrome/browser/tab_contents/thumbnail_generator_unittest.cc b/chrome/browser/tab_contents/thumbnail_generator_unittest.cc
index e79b77def93f00dca0005d08e8e2d877af4d774b..7963506525d376c21302df7e458e3002b8fe0197 100644
--- a/chrome/browser/tab_contents/thumbnail_generator_unittest.cc
+++ b/chrome/browser/tab_contents/thumbnail_generator_unittest.cc
@@ -191,23 +191,27 @@ TEST_F(ThumbnailGeneratorTest, ShouldUpdateThumbnail) {
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   scoped_refptr<MockTopSites> top_sites(new MockTopSites(&profile));
 
+  // Should be false when we don't have a surface available for copy
+  EXPECT_FALSE(ThumbnailGenerator::ShouldUpdateThumbnail(
+      &profile, top_sites.get(), kBadURL, false));
+
   // Should be false because it's a bad URL.
   EXPECT_FALSE(ThumbnailGenerator::ShouldUpdateThumbnail(
-      &profile, top_sites.get(), kBadURL));
+      &profile, top_sites.get(), kBadURL, true));
 
   // Should be true, as it's a good URL.
   EXPECT_TRUE(ThumbnailGenerator::ShouldUpdateThumbnail(
-      &profile, top_sites.get(), kGoodURL));
+      &profile, top_sites.get(), kGoodURL, true));
 
   // Should be false, if it's in the incognito mode.
   profile.set_incognito(true);
   EXPECT_FALSE(ThumbnailGenerator::ShouldUpdateThumbnail(
-      &profile, top_sites.get(), kGoodURL));
+      &profile, top_sites.get(), kGoodURL, true));
 
   // Should be true again, once turning off the incognito mode.
   profile.set_incognito(false);
   EXPECT_TRUE(ThumbnailGenerator::ShouldUpdateThumbnail(
-      &profile, top_sites.get(), kGoodURL));
+      &profile, top_sites.get(), kGoodURL, true));
 
   // Add a known URL. This makes the top sites data full.
   ThumbnailScore bad_score;
@@ -219,11 +223,11 @@ TEST_F(ThumbnailGeneratorTest, ShouldUpdateThumbnail) {
   // not known.
   const GURL kAnotherGoodURL("http://www.youtube.com/");
   EXPECT_FALSE(ThumbnailGenerator::ShouldUpdateThumbnail(
-      &profile, top_sites.get(), kAnotherGoodURL));
+      &profile, top_sites.get(), kAnotherGoodURL, true));
 
   // Should be true, as the existing thumbnail is bad (i.e need a better one).
   EXPECT_TRUE(ThumbnailGenerator::ShouldUpdateThumbnail(
-      &profile, top_sites.get(), kGoodURL));
+      &profile, top_sites.get(), kGoodURL, true));
 
   // Replace the thumbnail score with a really good one.
   ThumbnailScore good_score;
@@ -237,5 +241,5 @@ TEST_F(ThumbnailGeneratorTest, ShouldUpdateThumbnail) {
   // Should be false, as the existing thumbnail is good enough (i.e. don't
   // need to replace the existing thumbnail which is new and good).
   EXPECT_FALSE(ThumbnailGenerator::ShouldUpdateThumbnail(
-      &profile, top_sites.get(), kGoodURL));
+      &profile, top_sites.get(), kGoodURL, true));
 }