Use google::GLOG_WARNING instead of WARNING in tests to support MSVC.

- GLOG_NO_ABBREVIATED_SEVERITIES is the default on Windows, in which
  case google::WARNING is not defined.
- Remove Ceres-specific redefinition of WARNING in mock-log.h fork
  in place of using non-abbreviated severity in the one place in
  levenberg_marquardt_strategy_test where ScopedMockLog is actually
  used.
- Remove unnecessary dependency of gradient_checking_cost_function_test
  on ScopedMockLog.

Change-Id: I9fb540f638037b6015fd264cfc618c9d60f5686c

internal/ceres/gmock/mock-log.h

diff --git a/internal/ceres/gmock/mock-log.h b/internal/ceres/gmock/mock-log.h
index bce54ab..54669b7 100644
--- a/internal/ceres/gmock/mock-log.h
+++ b/internal/ceres/gmock/mock-log.h
@@ -44,13 +44,6 @@
 
 #include "glog/logging.h"
 
-// Needed to make the scoped mock log tests work without modification.
-namespace ceres {
-namespace internal {
-using google::WARNING;
-}  // namespace internal
-}  // namespace ceres
-
 namespace testing {
 
 // A ScopedMockLog object intercepts LOG() messages issued during its

internal/ceres/gradient_checking_cost_function_test.cc

diff --git a/internal/ceres/gradient_checking_cost_function_test.cc b/internal/ceres/gradient_checking_cost_function_test.cc
index e7238c6..887922e 100644
--- a/internal/ceres/gradient_checking_cost_function_test.cc
+++ b/internal/ceres/gradient_checking_cost_function_test.cc
@@ -45,7 +45,6 @@
 #include "ceres/types.h"
 #include "glog/logging.h"
 #include "gmock/gmock.h"
-#include "gmock/mock-log.h"
 #include "gtest/gtest.h"
 
 namespace ceres {
@@ -55,7 +54,6 @@
 using testing::AllOf;
 using testing::AnyNumber;
 using testing::HasSubstr;
-using testing::ScopedMockLog;
 using testing::_;
 
 // Pick a (non-quadratic) function whose derivative are easy:

internal/ceres/levenberg_marquardt_strategy_test.cc

diff --git a/internal/ceres/levenberg_marquardt_strategy_test.cc b/internal/ceres/levenberg_marquardt_strategy_test.cc
index 9a7bcb4..950ca23 100644
--- a/internal/ceres/levenberg_marquardt_strategy_test.cc
+++ b/internal/ceres/levenberg_marquardt_strategy_test.cc
@@ -145,7 +145,9 @@
   {
     ScopedMockLog log;
     EXPECT_CALL(log, Log(_, _, _)).Times(AnyNumber());
-    EXPECT_CALL(log, Log(WARNING, _,
+    // Use GLOG_WARNING to support MSVC if GLOG_NO_ABBREVIATED_SEVERITIES
+    // is defined.
+    EXPECT_CALL(log, Log(google::GLOG_WARNING, _,
                          HasSubstr("Failed to compute a step")));
 
     TrustRegionStrategy::Summary summary =