[Android WebView] Reflect system font scale in WebView text rendering.

android_webview/java/src/org/chromium/android_webview/AwSettings.java

Index: android_webview/java/src/org/chromium/android_webview/AwSettings.java
diff --git a/android_webview/java/src/org/chromium/android_webview/AwSettings.java b/android_webview/java/src/org/chromium/android_webview/AwSettings.java
index 6cc8e532ef99d5912feb9acabd0788e3eb1ebefc..6ba9ac698cad8a554060a357fbddb3378c3ee7c6 100644
--- a/android_webview/java/src/org/chromium/android_webview/AwSettings.java
+++ b/android_webview/java/src/org/chromium/android_webview/AwSettings.java
@@ -10,6 +10,7 @@ import android.os.Handler;
 import android.os.Message;
 import android.os.Process;
 import android.provider.Settings;
+import android.util.Log;
 import android.webkit.WebSettings;
 import android.webkit.WebSettings.PluginState;
 
@@ -87,6 +88,9 @@ public class AwSettings {
 
     private final boolean mPasswordEchoEnabled;
 
+    // Font scale factor determined by Android system setting.
+    private final float mFontScale;
+
     // Not accessed by the native side.
     private boolean mBlockNetworkLoads;  // Default depends on permission of embedding APK.
     private boolean mAllowContentUrlAccess = true;
@@ -181,7 +185,9 @@ public class AwSettings {
                     while (mIsUpdateWebkitPrefsMessagePending) {
                         mAwSettingsLock.wait();
                     }
-                } catch (InterruptedException e) {}
+                } catch (InterruptedException e) {
+                    Log.e(TAG, "Interrupted waiting to sync settings to native", e);
+                }
             }
         }
     }
@@ -215,6 +221,8 @@ public class AwSettings {
             // Respect the system setting for password echoing.
             mPasswordEchoEnabled = Settings.System.getInt(context.getContentResolver(),
                     Settings.System.TEXT_SHOW_PASSWORD, 1) == 1;
+            mFontScale = context.getResources().getConfiguration().fontScale;
+            mTextSizePercent *= mFontScale;
 
             mSupportLegacyQuirks = supportsLegacyQuirks;
         }
@@ -537,8 +545,9 @@ public class AwSettings {
      */
     public void setTextZoom(final int textZoom) {
         synchronized (mAwSettingsLock) {
-            if (mTextSizePercent != textZoom) {
-                mTextSizePercent = textZoom;
+            int scaledTextZoomPercent = (int)(textZoom * mFontScale);
+            if (mTextSizePercent != scaledTextZoomPercent) {
+                mTextSizePercent = scaledTextZoomPercent;
                 mEventHandler.updateWebkitPreferencesLocked();
             }
         }