Mark some flaky and failing tests as such.

chrome/test/ui/ppapi_uitest.cc

 // Copyright (c) 2010 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 "base/file_util.h"
 #include "base/path_service.h"
 #include "build/build_config.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/test/automation/tab_proxy.h"
 #include "chrome/test/ui/ui_test.h"
@@ skipping 73 matching lines @@
         WaitUntilCookieNonEmpty(tab.get(), test_url,
             "COMPLETION_COOKIE", action_max_timeout_ms());
     EXPECT_STREQ("PASS", escaped_value.c_str());
   }
 };
 
 TEST_F(PPAPITest, DeviceContext2D) {
   RunTest("DeviceContext2D");
 }
 
-TEST_F(PPAPITest, ImageData) {
+// TODO(brettw) bug 51344: this is flaky on bots. Seems to timeout navigating.
+// Possibly all the image allocations slow things down on a loaded bot too much.
+TEST_F(PPAPITest, FLAKY_ImageData) {
   RunTest("ImageData");
 }
 
 TEST_F(PPAPITest, Buffer) {
   RunTest("Buffer");
 }
 
-TEST_F(PPAPITest, URLLoader) {
+// TODO(brettw) bug 51345: this failed consistently on one of the bots.
+TEST_F(PPAPITest, FAILS_URLLoader) {
   RunTestViaHTTP("URLLoader");
 }
 
 // Flaky, http://crbug.com/51012
 TEST_F(PPAPITest, FLAKY_PaintAggregator) {
   RunTestViaHTTP("PaintAggregator");
 }
 
 #if defined(OS_LINUX)
 // Flaky, http://crbug.com/48544.
 TEST_F(PPAPITest, FLAKY_Scrollbar) {
 #else
 TEST_F(PPAPITest, Scrollbar) {
 #endif
   RunTest("Scrollbar");
 }
 
 TEST_F(PPAPITest, UrlUtil) {
   RunTest("UrlUtil");
 }