Use ::testing to not get mixed up with ::blink::testing

There is both a ::testing namespace and a blink::testing namespace
and if you inside namespace blink says "testing", which one you
get depends on what the compiler knows. In jumbo builds compilers
often know about both namespaces and will assume you mean
::blink::testing.

To be sure to get ::testing, you need to prefix it with ::.

In the long run ::blink::testing should probably be renamed. Its
name violates the rule that no sub namespace should have the same
name as a common top level namespace.

Change-Id: I60857ebd08d4b35ce56212d03b4ed63045803402
Reviewed-on: https://chromium-review.googlesource.com/978004
Commit-Queue: Kent Tamura <tkent@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#545717}

third_party/WebKit/Source/platform/text/HyphenationTest.cpp

@@ -134,7 +134,7 @@ TEST_F(HyphenationTest, LeadingSpaces) {
   // Line breaker is not supposed to pass with trailing spaces.
   String trailing_space("principle ");
   EXPECT_THAT(hyphenation->HyphenLocations(trailing_space),
-              testing::AnyOf(ElementsAre(), ElementsAre(6, 4)));
+              ::testing::AnyOf(ElementsAre(), ElementsAre(6, 4)));
   EXPECT_EQ(0u, hyphenation->LastHyphenLocation(trailing_space, 10));
 }
 
@@ -148,8 +148,8 @@ TEST_F(HyphenationTest, English) {
   ASSERT_TRUE(hyphenation) << "Cannot find the hyphenation for en-us";
 
   Vector<size_t, 8> locations = hyphenation->HyphenLocations("hyphenation");
-  EXPECT_THAT(locations, testing::AnyOf(ElementsAreArray({6, 2}),
-                                        ElementsAreArray({7, 6, 2})));
+  EXPECT_THAT(locations, ::testing::AnyOf(ElementsAreArray({6, 2}),
+                                          ElementsAreArray({7, 6, 2})));
 }
 
 TEST_F(HyphenationTest, German) {