[TTS] Fix tap-far-from-previous suppression.

A tap that's far from the previous tap should generally be ignored,
and just dismiss our UI instead of starting a new tap-handling sequence.
This CL updates our logic to look at whether there was any selection
before the tap rather than whether the previous tap was suppressed.

Our old logic ignored whether there was any selection before the tap,
and used whether the previous tap was suppressed as a proxy for
no-selection.  Recent code changes make it fairly easy to determine
if there was a selection just before a tap gesture so we use that
instead.

The difference becomes clear when "invalid taps" are considered.
These are taps on non-text characters, e.g. a period or comma.  These
taps don't select, but they also are not technically suppressed, so
a subsequent tap would be ignored.  Now any tap that's far from a previous
tap will be ignored only if there was a selection before the tap.

BUG=713471

Change-Id: Ie94e345a87cf580a3d1993370938982e6e273e89
Reviewed-on: https://chromium-review.googlesource.com/794020Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Donn Denman <donnd@chromium.org>
Cr-Commit-Position: refs/heads/master@{#520161}

chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchSelectionController.java

@@ -76,6 +76,9 @@ public class ContextualSearchSelectionController {
     // When the last tap gesture happened.
     private long mTapTimeNanoseconds;
 
+    // Whether the selection was empty before the most recent tap gesture.
+    private boolean mWasSelectionEmptyBeforeTap;
+
     // The duration of the last tap gesture in milliseconds, or 0 if not set.
     private int mTapDurationMs = INVALID_DURATION;
 
@@ -100,6 +103,7 @@ public class ContextualSearchSelectionController {
         @Override
         public void onTouchDown() {
             mTapTimeNanoseconds = System.nanoTime();
+            mWasSelectionEmptyBeforeTap = TextUtils.isEmpty(mSelectedText);
         }
     }
 
@@ -361,8 +365,9 @@ public class ContextualSearchSelectionController {
         int adjustedTapsSinceOpen = prefs.getContextualSearchTapCount()
                 - prefs.getContextualSearchTapQuickAnswerCount();
         assert mTapDurationMs != INVALID_DURATION : "mTapDurationMs not set!";
-        TapSuppressionHeuristics tapHeuristics = new TapSuppressionHeuristics(this, mLastTapState,
-                x, y, adjustedTapsSinceOpen, contextualSearchContext, mTapDurationMs);
+        TapSuppressionHeuristics tapHeuristics =
+                new TapSuppressionHeuristics(this, mLastTapState, x, y, adjustedTapsSinceOpen,
+                        contextualSearchContext, mTapDurationMs, mWasSelectionEmptyBeforeTap);
         // TODO(donnd): Move to be called when the panel closes to work with states that change.
         tapHeuristics.logConditionState();
 

chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/TapFarFromPreviousSuppression.java

@@ -4,6 +4,8 @@
 
 package org.chromium.chrome.browser.contextualsearch;
 
+import android.support.annotation.Nullable;
+
 /**
  * Implements the policy that a Tap relatively far away from an existing Contextual Search
  * selection should just dismiss our UX.  When a Tap is close by, we assume the user must have
@@ -20,14 +22,17 @@ class TapFarFromPreviousSuppression extends ContextualSearchHeuristic {
      * Constructs a heuristic to determine if the current Tap should be suppressed because it is
      * far from the previous tap.
      * @param controller The {@link ContextualSearchSelectionController}.
+     * @param previousTapState The state of the previous tap gesture, or {@code null}.
      * @param x The x coordinate of the tap gesture.
      * @param y The y coordinate of the tap gesture.
+     * @param wasSelectionEmptyBeforeTap Whether the selection was empty just before this tap.
      */
     TapFarFromPreviousSuppression(ContextualSearchSelectionController controller,
-            ContextualSearchTapState previousTapState, int x, int y) {
+            @Nullable ContextualSearchTapState previousTapState, int x, int y,
+            boolean wasSelectionEmptyBeforeTap) {
         mPxToDp = controller.getPxToDp();
         mPreviousTapState = previousTapState;
-        mShouldHandleTap = shouldHandleTap(x, y);
+        mShouldHandleTap = shouldHandleTap(x, y, wasSelectionEmptyBeforeTap);
     }
 
     @Override
@@ -36,17 +41,21 @@ class TapFarFromPreviousSuppression extends ContextualSearchHeuristic {
     }
 
     /**
+     * Determines whether the tap should be handled based on whether it's near a previous tap and
+     * whether the selection was visible just before that tap.  Uses the previous tap state.
+     * @param x The x coordinate of the current tap.
+     * @param y The y coordinate of the current tap.
+     * @param wasSelectionEmptyBeforeTap Whether the selection was empty before the current tap.
      * @return whether a tap at the given coordinates should be handled or not.
      */
-    private boolean shouldHandleTap(int x, int y) {
-        if (mPreviousTapState == null) return true;
+    private boolean shouldHandleTap(int x, int y, boolean wasSelectionEmptyBeforeTap) {
+        if (mPreviousTapState == null || wasSelectionEmptyBeforeTap) return true;
 
-        return mPreviousTapState.wasSuppressed() || wasTapCloseToPreviousTap(x, y);
+        return wasTapCloseToPreviousTap(x, y);
     }
 
     /**
-     * Determines whether a tap at the given coordinates is considered "close" to the previous
-     * tap.
+     * @return Whether a tap at the given coordinates is considered "close" to the previous tap.
      */
     private boolean wasTapCloseToPreviousTap(int x, int y) {
         float deltaXDp = (mPreviousTapState.getX() - x) * mPxToDp;

chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/TapSuppressionHeuristics.java

@@ -4,6 +4,8 @@
 
 package org.chromium.chrome.browser.contextualsearch;
 
+import android.support.annotation.Nullable;
+
 /**
  * A set of {@link ContextualSearchHeuristic}s that support experimentation and logging.
  */
@@ -17,16 +19,20 @@ public class TapSuppressionHeuristics extends ContextualSearchHeuristics {
      * @param x The x position of the Tap.
      * @param y The y position of the Tap.
      * @param tapsSinceOpen the number of Tap gestures since the last open of the panel.
+     * @param contextualSearchContext The {@link ContextualSearchContext} of this tap.
+     * @param tapDurationMs The duration of this tap in milliseconds.
+     * @param wasSelectionEmptyBeforeTap Whether the selection was empty before this tap.
      */
     TapSuppressionHeuristics(ContextualSearchSelectionController selectionController,
-            ContextualSearchTapState previousTapState, int x, int y, int tapsSinceOpen,
-            ContextualSearchContext contextualSearchContext, int tapDurationMs) {
+            @Nullable ContextualSearchTapState previousTapState, int x, int y, int tapsSinceOpen,
+            ContextualSearchContext contextualSearchContext, int tapDurationMs,
+            boolean wasSelectionEmptyBeforeTap) {
         super();
         mCtrSuppression = new CtrSuppression();
         mHeuristics.add(mCtrSuppression);
         mHeuristics.add(new RecentScrollTapSuppression(selectionController));
-        mHeuristics.add(
-                new TapFarFromPreviousSuppression(selectionController, previousTapState, x, y));
+        mHeuristics.add(new TapFarFromPreviousSuppression(
+                selectionController, previousTapState, x, y, wasSelectionEmptyBeforeTap));
         mHeuristics.add(new TapDurationSuppression(tapDurationMs));
         mHeuristics.add(new TapWordLengthSuppression(contextualSearchContext));
         mHeuristics.add(new TapWordEdgeSuppression(contextualSearchContext));