[TTS] Fix crash calling KitKat+ API without check.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchContext.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchContext.java b/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchContext.java
index 39f330c99f92492b1a48da8c719ef7f016b82c1a..e8b55e0754770d82955b7be825ce3e0538370b50 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchContext.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchContext.java
@@ -5,6 +5,7 @@
 package org.chromium.chrome.browser.contextualsearch;
 
 import android.annotation.SuppressLint;
+import android.os.Build;
 import android.text.TextUtils;
 
 import org.chromium.base.annotations.CalledByNative;
@@ -278,7 +279,7 @@ public abstract class ContextualSearchContext {
     private int findWordStartOffset(String text, int initial) {

[Theresa, 2017/06/02 21:51:42]

This is just used to generate a ranker signal for whether the user tapped on the
edge of a word the middle, right?

[Donn Denman, 2017/06/02 22:00:42]

Correct, so it's non-critical for the feature.

         // Scan before, aborting if we hit any ideographic letter.
         for (int offset = initial - 1; offset >= 0; offset--) {
-            if (isIdeographicAtIndex(text, offset)) return INVALID_OFFSET;
+            if (isUnreliableWordBreakAtIndex(text, offset)) return INVALID_OFFSET;
 
             if (isWordBreakAtIndex(text, offset)) {
                 // The start of the word is after this word break.
@@ -301,7 +302,7 @@ public abstract class ContextualSearchContext {
     private int findWordEndOffset(String text, int initial) {
         // Scan after, aborting if we hit any CJKN letter.
         for (int offset = initial; offset < text.length(); offset++) {
-            if (isIdeographicAtIndex(text, offset)) return INVALID_OFFSET;
+            if (isUnreliableWordBreakAtIndex(text, offset)) return INVALID_OFFSET;
 
             if (isWordBreakAtIndex(text, offset)) {
                 // The end of the word is the offset of this word break.
@@ -312,12 +313,17 @@ public abstract class ContextualSearchContext {
     }
 
     /**
-     * @return Whether the character at the given index in the text is "Ideographic" (as in CJKV
-     *         languages), which means there may not be reliable word breaks.
+     * @return Whether the character at the given index in the text might be in an alphabet that has
+     *         unreliable word breaks, such as CKJV languages.  Returns {@code true} on older
+     *         platforms where we can't know for sure.
      */
     @SuppressLint("NewApi")
-    private boolean isIdeographicAtIndex(String text, int index) {
-        return Character.isIdeographic(text.charAt(index));
+    private boolean isUnreliableWordBreakAtIndex(String text, int index) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
+            return Character.isIdeographic(text.charAt(index));
+        } else {
+            return true; // Assume the worst if we can't check.
+        }
     }
 
     /**