Switching Clank to use direction-based selection granularity strategy and adding a chrome flag.

content/public/common/content_switches.cc

Index: content/public/common/content_switches.cc
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index f9b5801177ce6e5ce67172934ce1a224e3b09237..cc0fbabb585e787427e3e9e37adc449e4f835fc4 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -789,6 +789,11 @@ const char kTestingFixedHttpsPort[]         = "testing-fixed-https-port";
 // Type of the current test harness ("browser" or "ui").
 const char kTestType[]                      = "test-type";
 
+// Controls how text selection granularity changes when touch text selection
+// handles are dragged. Should be "character" or "direction". If not specified,
+// the platform default is used.
+const char kTouchTextSelectionStrategy[]    = "touch-selection-strategy";
+
 // Causes TRACE_EVENT flags to be recorded beginning with shutdown. Optionally,
 // can specify the specific trace categories to include (e.g.
 // --trace-shutdown=base,net) otherwise, all events are recorded.