Add flag to force complex text for tests

third_party/WebKit/Source/platform/fonts/Font.cpp

Index: third_party/WebKit/Source/platform/fonts/Font.cpp
diff --git a/third_party/WebKit/Source/platform/fonts/Font.cpp b/third_party/WebKit/Source/platform/fonts/Font.cpp
index be6e9d4047895800d3724d0df3d70e77631afe6e..77ab8d9edceab239d6d7d92dddfa284ee512c43e 100644
--- a/third_party/WebKit/Source/platform/fonts/Font.cpp
+++ b/third_party/WebKit/Source/platform/fonts/Font.cpp
@@ -25,6 +25,7 @@
 #include "config.h"
 #include "platform/fonts/Font.h"
 
+#include "platform/LayoutTestSupport.h"
 #include "platform/LayoutUnit.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/fonts/Character.h"
@@ -310,8 +311,10 @@ int Font::offsetForPosition(const TextRun& run, float x, bool includePartialGlyp
 
 CodePath Font::codePath(const TextRunPaintInfo& runInfo) const
 {
-    if (RuntimeEnabledFeatures::alwaysUseComplexTextEnabled())
+    if (RuntimeEnabledFeatures::alwaysUseComplexTextEnabled()
+        || LayoutTestSupport::alwaysUseComplexTextForTest()) {
         return ComplexPath;
+    }
 
     const TextRun& run = runInfo.run;