[chromecast] Separate margin flag for bottom gesture.

Allows the margin allowed for the bottom system gesture to be
specified separately from the top.

Bug: internal b/111304882
Test: manual
Change-Id: Ie549f2b7d48a4533eb5f493ed9255cf6ef6898d1
Reviewed-on: https://chromium-review.googlesource.com/1138395Reviewed-by: Alex Sakhartchouk <alexst@chromium.org>
Commit-Queue: Alex Sakhartchouk <alexst@chromium.org>
Commit-Queue: Ryan Daum <rdaum@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575289}

chromecast/base/chromecast_switches.cc

@@ -139,13 +139,21 @@ const char kEnableInput[] = "enable-input";
 const char kCastAppBackgroundColor[] = "cast-app-background-color";
 
 // The number of pixels from the very left or right of the screen to consider as
-// a valid origin for the left or right swipe gesture.
+// a valid origin for the left or right swipe gesture.  Overrides the default
+// value in cast_system_gesture_handler.cc.
 const char kSystemGestureStartWidth[] = "system-gesture-start-width";
 
 // The number of pixels from the very top or bottom of the screen to consider as
-// a valid origin for the top or bottom swipe gesture.
+// a valid origin for the top or bottom swipe gesture. Overrides the default
+// value in cast_system_gesture_handler.cc.
 const char kSystemGestureStartHeight[] = "system-gesture-start-height";
 
+// The number of pixels up from the bottom of the screen to consider as a valid
+// origin for a bottom swipe gesture. If set, overrides the value of both the
+// above system-gesture-start-height flag and the default value in
+// cast_system_gesture_handler.cc.
+const char kBottomSystemGestureStartHeight[] = "bottom-gesture-start-height";
+
 // The number of pixels from the start of a left swipe gesture to consider as a
 // 'back' gesture.
 const char kBackGestureHorizontalThreshold[] =

chromecast/base/chromecast_switches.h

@@ -74,6 +74,7 @@ extern const char kForceMediaResolutionWidth[];
 extern const char kEnableInput[];
 extern const char kSystemGestureStartWidth[];
 extern const char kSystemGestureStartHeight[];
+extern const char kBottomSystemGestureStartHeight[];
 extern const char kBackGestureHorizontalThreshold[];
 extern const char kEnableTopDragGesture[];
 

chromecast/graphics/cast_system_gesture_event_handler.cc

@@ -25,6 +25,15 @@ constexpr int kDefaultSideGestureStartWidth = 35;
 // a valid origin for the top or bottom swipe gesture.
 constexpr int kDefaultSideGestureStartHeight = 35;
 
+// Get the correct bottom gesture start height by checking both margin flags in
+// order, and then the default value if neither is set.
+int BottomGestureStartHeight() {
+  return GetSwitchValueInt(
+      switches::kBottomSystemGestureStartHeight,
+      GetSwitchValueInt(switches::kSystemGestureStartHeight,
+                        kDefaultSideGestureStartHeight));
+}
+
 }  // namespace
 
 CastSystemGestureEventHandler::CastSystemGestureEventHandler(
@@ -35,6 +44,7 @@ CastSystemGestureEventHandler::CastSystemGestureEventHandler(
       gesture_start_height_(
           GetSwitchValueInt(switches::kSystemGestureStartHeight,
                             kDefaultSideGestureStartHeight)),
+      bottom_gesture_start_height_(BottomGestureStartHeight()),
       root_window_(root_window),
       current_swipe_(CastSideSwipeOrigin::NONE) {
   DCHECK(root_window);
@@ -59,8 +69,8 @@ CastSideSwipeOrigin CastSystemGestureEventHandler::GetDragPosition(
       (screen_bounds.x() + screen_bounds.width() - gesture_start_width_)) {
     return CastSideSwipeOrigin::RIGHT;
   }
-  if (point.y() >
-      (screen_bounds.y() + screen_bounds.height() - gesture_start_height_)) {
+  if (point.y() > (screen_bounds.y() + screen_bounds.height() -
+                   bottom_gesture_start_height_)) {
     return CastSideSwipeOrigin::BOTTOM;
   }
   return CastSideSwipeOrigin::NONE;

chromecast/graphics/cast_system_gesture_event_handler.h

@@ -48,6 +48,7 @@ class CastSystemGestureEventHandler : public ui::EventHandler {
  private:
   const int gesture_start_width_;
   const int gesture_start_height_;
+  const int bottom_gesture_start_height_;
 
   aura::Window* root_window_;
   CastSideSwipeOrigin current_swipe_;