Add flag to force complex text for tests

content/shell/common/shell_switches.cc

Index: content/shell/common/shell_switches.cc
diff --git a/content/shell/common/shell_switches.cc b/content/shell/common/shell_switches.cc
index 9bce7af1585b11efc37dcf91c4dd61446c60d5b6..df7d3fe84f50314620d14613d480277d36eea4b5 100644
--- a/content/shell/common/shell_switches.cc
+++ b/content/shell/common/shell_switches.cc
@@ -41,6 +41,9 @@ const char kEnableAccelerated2DCanvas[] = "enable-accelerated-2d-canvas";
 // Enable font antialiasing for pixel tests.
 const char kEnableFontAntialiasing[] = "enable-font-antialiasing";
 
+// Always use the complex text path for layout tests.
+const char kAlwaysUseComplexText[] = "always-use-complex-text";
+
 // Enables the leak detection of loading webpages. This allows us to check
 // whether or not reloading a webpage releases web-related objects correctly.
 const char kEnableLeakDetection[] = "enable-leak-detection";