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

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 48d8576df52e2bada55ba35d105fac803873b2d6..4e17cd32e329b7b1f9bf64f303c19247f35e47e6 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -178,6 +178,16 @@ const Experiment::Choice kOverscrollHistoryNavigationChoices[] = {
 };
 #endif
 
+const Experiment::Choice kTouchTextSelectionStrategyChoices[] = {
+  { IDS_GENERIC_EXPERIMENT_CHOICE_DEFAULT, "", "" },
+  { IDS_TOUCH_SELECTION_STRATEGY_CHARACTER,
+    switches::kTouchTextSelectionStrategy,

[jdduke (slow), 2015/04/21 14:45:08]

I can't say I love the use of ordinals to describe the strategy. People wanting
to "experiment" will have to look at the soure before they're able to make a
change. Any reason to use integers instead of string constants?

[mfomitchev, 2015/04/21 15:02:37]

These will shown as strings in the about://flags UI: Default, Character, and
Direction (see generated_resources.grd). I suppose I could turn "0" and "1" into
"character" and "direction" as well. I don't have much of an opinion either way
- I just copied kOverscrollHistoryNavigationChoices figuring it's better to be
consistent.

[jdduke (slow), 2015/04/21 15:13:40]

Ah, I didn't realize the names already get pretty printed, definitely fine as-is
for me!

+    "0" },
+  { IDS_TOUCH_SELECTION_STRATEGY_DIRECTION,
+    switches::kTouchTextSelectionStrategy,
+    "1" }
+};
+
 #if !defined(DISABLE_NACL)
 const Experiment::Choice kNaClDebugMaskChoices[] = {
   // Secure shell can be used on ChromeOS for forwarding the TCP port opened by
@@ -1200,6 +1210,13 @@ const Experiment kExperiments[] = {
                               switches::kDisableTouchEditing)
   },
   {
+      "touch-selection-strategy",

[jdduke (slow), 2015/04/17 17:05:16]

"touch-selection-strategy" values of 0/1 don't really tell us anything. Can we
just call this |kEnableSmartTextSelection| with an appropriate flag description,
and use that to determine the right strategy/granularity?

[mfomitchev, 2015/04/17 17:14:37]

Eventually I'd like to add another strategy: shrink by character only until the
word boundary and then switch to word granularity if you continue shrinking.
Then we will have three strategies, and enable/disable won't work.

[jdduke (slow), 2015/04/17 19:03:35]

Acknowledged.

+      IDS_FLAGS_TOUCH_SELECTION_STRATEGY_NAME,
+      IDS_FLAGS_TOUCH_SELECTION_STRATEGY_DESCRIPTION,
+      kOsAndroid,   // TODO(mfomitchev): Add CrOS/Win/Linux support soon.
+      MULTI_VALUE_TYPE(kTouchTextSelectionStrategyChoices)
+  },
+  {
     "enable-stale-while-revalidate",
     IDS_FLAGS_ENABLE_STALE_WHILE_REVALIDATE_NAME,
     IDS_FLAGS_ENABLE_STALE_WHILE_REVALIDATE_DESCRIPTION,