Bug 1442176 - 2. Add pinned-to-screen flag in GeckoSession; r=snorp r=droeh

Add a flag for whether the session should be pinned to the screen. The
app would check the flag and prevent scrolling of the session when it's
pinned.

Differential Revision: https://phabricator.services.mozilla.com/D5190

mobile/android/chrome/geckoview/GeckoViewContent.js

@@ -49,6 +49,7 @@ class GeckoViewContent extends GeckoViewContentModule {
     addEventListener("pageshow", this, options);
     addEventListener("focusin", this, options);
     addEventListener("focusout", this, options);
+    addEventListener("mozcaretstatechanged", this, options);
 
     XPCOMUtils.defineLazyGetter(this, "_autoFill", () =>
         new GeckoViewAutoFill(this.eventDispatcher));
@@ -236,6 +237,7 @@ class GeckoViewContent extends GeckoViewContentModule {
     }
   }
 
+  // eslint-disable-next-line complexity
   handleEvent(aEvent) {
     debug `handleEvent: ${aEvent.type}`;
 
@@ -336,6 +338,14 @@ class GeckoViewContent extends GeckoViewContentModule {
           this._autoFill.scanDocument(aEvent.target);
         }
         break;
+      case "mozcaretstatechanged":
+        if (aEvent.reason === "presscaret" || aEvent.reason === "releasecaret") {
+          this.eventDispatcher.sendRequest({
+            type: "GeckoView:PinOnScreen",
+            pinned: aEvent.reason === "presscaret",
+          });
+        }
+        break;
     }
   }
 

mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/LayerSession.java

@@ -475,6 +475,16 @@ public class LayerSession {
         mOverscroll.setDistance(y, OverscrollEdgeEffect.AXIS_Y);
     }
 
+    protected void setShouldPinOnScreen(final boolean pinned) {
+        if (DEBUG) {
+            ThreadUtils.assertOnUiThread();
+        }
+
+        if (mToolbar != null) {
+            mToolbar.setPinned(pinned, DynamicToolbarAnimator.PinReason.CARET_DRAG);
+        }
+    }
+
     /* package */ void onMetricsChanged(final float scrollX, final float scrollY,
                                         final float zoom) {
         if (DEBUG) {

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoDisplay.java

@@ -59,4 +59,17 @@ public class GeckoDisplay {
             session.onScreenOriginChanged(left, top);
         }
     }
+
+    /**
+     * Return whether the display should be pinned on the screen. When pinned, the display
+     * should not be moved on the screen due to animation, scrolling, etc. A common reason
+     * for the display being pinned is when the user is dragging a selection caret inside
+     * the display; normal user interaction would be disrupted in that case if the display
+     * was moved on screen.
+     *
+     * @return True if display should be pinned on the screen.
+     */
+    public boolean shouldPinOnScreen() {
+        return session.getDisplay() == this && session.shouldPinOnScreen();
+    }
 }

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoSession.java

@@ -101,6 +101,8 @@ public final class GeckoSession extends LayerSession
     private String mId = UUID.randomUUID().toString().replace("-", "");
     /* package */ String getId() { return mId; }
 
+    private boolean mShouldPinOnScreen;
+
     /* package */ static abstract class CallbackResult<T> extends GeckoResult<T>
                                                           implements EventCallback {
         @Override
@@ -813,6 +815,7 @@ public final class GeckoSession extends LayerSession
     private class Listener implements BundleEventListener {
         /* package */ void registerListeners() {
             getEventDispatcher().registerUiThreadListener(this,
+                "GeckoView:PinOnScreen",
                 "GeckoView:Prompt",
                 null);
         }
@@ -824,7 +827,9 @@ public final class GeckoSession extends LayerSession
                 Log.d(LOGTAG, "handleMessage: event = " + event);
             }
 
-            if ("GeckoView:Prompt".equals(event)) {
+            if ("GeckoView:PinOnScreen".equals(event)) {
+                GeckoSession.this.setShouldPinOnScreen(message.getBoolean("pinned"));
+            } else if ("GeckoView:Prompt".equals(event)) {
                 handlePromptEvent(GeckoSession.this, message, callback);
             }
         }
@@ -1992,6 +1997,17 @@ public final class GeckoSession extends LayerSession
         }
     }
 
+    @Override
+    protected void setShouldPinOnScreen(final boolean pinned) {
+        super.setShouldPinOnScreen(pinned);
+        mShouldPinOnScreen = pinned;
+    }
+
+    /* package */ boolean shouldPinOnScreen() {
+        ThreadUtils.assertOnUiThread();
+        return mShouldPinOnScreen;
+    }
+
     public EventDispatcher getEventDispatcher() {
         return mEventDispatcher;
     }

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoView.java

@@ -159,6 +159,10 @@ public class GeckoView extends FrameLayout {
                 mDisplay.screenOriginChanged(mOrigin[0], mOrigin[1]);
             }
         }
+
+        public boolean shouldPinOnScreen() {
+            return mDisplay != null ? mDisplay.shouldPinOnScreen() : false;
+        }
     }
 
     public GeckoView(final Context context) {
@@ -212,6 +216,19 @@ public class GeckoView extends FrameLayout {
         }
     }
 
+    /**
+     * Return whether the view should be pinned on the screen. When pinned, the view
+     * should not be moved on the screen due to animation, scrolling, etc. A common reason
+     * for the view being pinned is when the user is dragging a selection caret inside
+     * the view; normal user interaction would be disrupted in that case if the view
+     * was moved on screen.
+     *
+     * @return True if view should be pinned on the screen.
+     */
+    public boolean shouldPinOnScreen() {
+        return mDisplay.shouldPinOnScreen();
+    }
+
     /* package */ void setActive(final boolean active) {
         if (mSession != null) {
             mSession.setActive(active);