capture_mode: Keyboard shortcuts to create/resize a region.

Add the following keyboard shortcuts to a capture session.

Space: Creates a default region 1/12th the size of the root.
Tab: Cycles through and highlights the region and affordance circles.
  Also handles events as these were affecting the top window.
Arrow keys: Shifts the region if it is focused, resizes the region if
  a affordance circle is focused.

Not in this CL:
  - moving focus to capture bar/capture button, requires those widgets
    to be focusable
  - leave focus on mouse click and start tabbing from the last mouse
    click

Bug: 1154778
Test: manual, added test
Change-Id: Ib4adf61e93bc7ad759fb33bac3185d069de0da65
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2575325
Commit-Queue: Sammie Quon <sammiequon@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#836336}

ash/capture_mode/capture_mode_constants.h

@@ -27,6 +27,10 @@ constexpr SkColor kInkDropBaseColor = SK_ColorWHITE;
 // CaptureModeBarView.
 constexpr int kBetweenChildSpacing = 16;
 
+// The amount the capture region changes when using the arrow keys to adjust it.
+constexpr int kArrowKeyboardRegionChangeDp = 1;
+constexpr int kShiftArrowKeyboardRegionChangeDp = 10;
+
 }  // namespace capture_mode
 
 }  // namespace ash

ash/capture_mode/capture_mode_session.h

@@ -217,6 +217,19 @@ class ASH_EXPORT CaptureModeSession : public ui::LayerOwner,
   void EndSelection(bool is_event_on_capture_bar,
                     bool region_intersects_capture_bar);
 
+  // Schedules a paint on the region and enough inset around it so that the
+  // shadow, affordance circles, etc. are all repainted.
+  void RepaintRegion();
+
+  // Selects a default region that is centered and whose size is a ratio of the
+  // root window bounds. Called when the space key is pressed.
+  void SelectDefaultRegion();
+
+  // Updates the region either horizontally or vertically. Called when the arrow
+  // keys are pressed.
+  void UpdateRegionHorizontally(bool left, bool is_shift_down);
+  void UpdateRegionVertically(bool up, bool is_shift_down);
+
   CaptureModeController* const controller_;
 
   // The current root window on which the capture session is active, which may
@@ -286,6 +299,10 @@ class ASH_EXPORT CaptureModeSession : public ui::LayerOwner,
   // True if at any point during the lifetime of |this|, the capture source
   // changed. Used for metrics collection.
   bool capture_source_changed_ = false;
+
+  // The current focused fine tune position. This changes as user tabs while a
+  // in capture region mode.
+  FineTunePosition focused_fine_tune_position_ = FineTunePosition::kNone;
 };
 
 }  // namespace ash

ash/capture_mode/capture_mode_unittests.cc

@@ -6,6 +6,7 @@
 
 #include "ash/capture_mode/capture_mode_bar_view.h"
 #include "ash/capture_mode/capture_mode_button.h"
+#include "ash/capture_mode/capture_mode_constants.h"
 #include "ash/capture_mode/capture_mode_controller.h"
 #include "ash/capture_mode/capture_mode_metrics.h"
 #include "ash/capture_mode/capture_mode_session.h"
@@ -71,9 +72,11 @@ void ClickOnView(const views::View* view,
 }
 
 void SendKey(ui::KeyboardCode key_code,
-             ui::test::EventGenerator* event_generator) {
-  event_generator->PressKey(key_code, /*flags=*/0);
-  event_generator->ReleaseKey(key_code, /*flags=*/0);
+             ui::test::EventGenerator* event_generator,
+             bool shift_down = false) {
+  int flags = shift_down ? ui::EF_SHIFT_DOWN : 0;
+  event_generator->PressKey(key_code, flags);
+  event_generator->ReleaseKey(key_code, flags);
 }
 
 // Moves the mouse and updates the cursor's display manually to imitate what a
@@ -1945,6 +1948,68 @@ TEST_F(CaptureModeTest, ReenterOnSmallerDisplay) {
   EXPECT_EQ(gfx::Rect(600, 400), controller->user_capture_region());
 }
 
+// Tests that functionality to create and adjust a region with keyboard
+// shortcuts works as intended.
+TEST_F(CaptureModeTest, SelectRegionWithKeyboard) {
+  auto* controller = StartImageRegionCapture();
+  auto* event_generator = GetEventGenerator();
+  ASSERT_TRUE(controller->user_capture_region().IsEmpty());
+
+  // Test that hitting space will create a default region.
+  SendKey(ui::VKEY_SPACE, event_generator);
+  gfx::Rect capture_region = controller->user_capture_region();
+  EXPECT_FALSE(capture_region.IsEmpty());
+
+  // Test that hitting an arrow key will do nothing as nothing is focused
+  // initially.
+  SendKey(ui::VKEY_RIGHT, event_generator);
+  EXPECT_EQ(capture_region, controller->user_capture_region());
+
+  const int arrow_shift = capture_mode::kArrowKeyboardRegionChangeDp;
+
+  // Hit tab so that the whole region is focused. Arrow keys should shift the
+  // whole region.
+  SendKey(ui::VKEY_TAB, event_generator);
+  SendKey(ui::VKEY_RIGHT, event_generator);
+  EXPECT_EQ(capture_region.origin() + gfx::Vector2d(arrow_shift, 0),
+            controller->user_capture_region().origin());
+  EXPECT_EQ(capture_region.size(), controller->user_capture_region().size());
+  SendKey(ui::VKEY_RIGHT, event_generator, /*shift_down=*/true);
+  EXPECT_EQ(
+      capture_region.origin() +
+          gfx::Vector2d(
+              arrow_shift + capture_mode::kShiftArrowKeyboardRegionChangeDp, 0),
+      controller->user_capture_region().origin());
+  EXPECT_EQ(capture_region.size(), controller->user_capture_region().size());
+
+  // Hit tab so that the top left affordance circle is focused. Left and up keys
+  // should enlarge the region, right and bottom keys should shrink the region.
+  capture_region = controller->user_capture_region();
+  SendKey(ui::VKEY_TAB, event_generator);
+  SendKey(ui::VKEY_LEFT, event_generator);
+  SendKey(ui::VKEY_UP, event_generator);
+  EXPECT_EQ(capture_region.size() + gfx::Size(arrow_shift, arrow_shift),
+            controller->user_capture_region().size());
+  SendKey(ui::VKEY_RIGHT, event_generator);
+  SendKey(ui::VKEY_DOWN, event_generator);
+  EXPECT_EQ(capture_region.size(), controller->user_capture_region().size());
+
+  // Tab until we focus the bottom right affordance circle. Left and up keys
+  // should shrink the region, right and bottom keys should enlarge the region.
+  SendKey(ui::VKEY_TAB, event_generator);
+  SendKey(ui::VKEY_TAB, event_generator);
+  SendKey(ui::VKEY_TAB, event_generator);
+  SendKey(ui::VKEY_TAB, event_generator);
+
+  SendKey(ui::VKEY_LEFT, event_generator);
+  SendKey(ui::VKEY_UP, event_generator);
+  EXPECT_EQ(capture_region.size() - gfx::Size(arrow_shift, arrow_shift),
+            controller->user_capture_region().size());
+  SendKey(ui::VKEY_RIGHT, event_generator);
+  SendKey(ui::VKEY_DOWN, event_generator);
+  EXPECT_EQ(capture_region.size(), controller->user_capture_region().size());
+}
+
 // A test class that uses a mock time task environment.
 class CaptureModeMockTimeTest : public CaptureModeTest {
  public:

ash/shell_tab_handler.cc

@@ -4,7 +4,9 @@
 
 #include "shell_tab_handler.h"
 
+#include "ash/capture_mode/capture_mode_controller.h"
 #include "ash/focus_cycler.h"
+#include "ash/public/cpp/ash_features.h"
 #include "ash/shelf/shelf.h"
 #include "ash/shelf/shelf_navigation_widget.h"
 #include "ash/shell.h"
@@ -27,6 +29,12 @@ void ShellTabHandler::OnKeyEvent(ui::KeyEvent* key_event) {
     return;
   }
 
+  // Capture session will process their own tab events.
+  if (features::IsCaptureModeEnabled() &&
+      CaptureModeController::Get()->IsActive()) {
+    return;
+  }
+
   aura::Window* root_window_for_new_windows =
       Shell::GetRootWindowForNewWindows();