Fix animation issues with extensions container.

This leverages some new built-in functionality in FlexLayout and
AnimatingLayoutManager to make the icon container behave the way we want
it to in most (hopefully all!) cases.

Bug: 995448
Change-Id: I349f1e3dd57669848f936e9b531797bc087bad50
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1968244Reviewed-by: Caroline Rising <corising@chromium.org>
Commit-Queue: Dana Fried <dfried@chromium.org>
Cr-Commit-Position: refs/heads/master@{#725610}

chrome/browser/ui/views/extensions/extensions_toolbar_container.cc

@@ -15,6 +15,9 @@
 #include "chrome/browser/ui/views/extensions/extensions_toolbar_button.h"
 #include "chrome/browser/ui/views/toolbar/toolbar_actions_bar_bubble_views.h"
 #include "ui/views/layout/animating_layout_manager.h"
+#include "ui/views/layout/flex_layout.h"
+#include "ui/views/layout/flex_layout_types.h"
+#include "ui/views/view_class_properties.h"
 #include "ui/views/widget/widget_observer.h"
 
 struct ExtensionsToolbarContainer::DropInfo {
@@ -41,7 +44,16 @@ ExtensionsToolbarContainer::ExtensionsToolbarContainer(Browser* browser)
   model_observer_.Add(model_);
   // Do not flip the Extensions icon in RTL.
   extensions_button_->EnableCanvasFlippingForRTLUI(false);
+  extensions_button_->SetProperty(views::kFlexBehaviorKey,
+                                  views::FlexSpecification());
   AddMainButton(extensions_button_);
+  target_layout_manager()
+      ->SetFlexAllocationOrder(views::FlexAllocationOrder::kReverse)
+      .SetDefault(views::kFlexBehaviorKey,
+                  views::FlexSpecification::ForSizeRule(
+                      views::MinimumFlexSizeRule::kPreferredSnapToZero,
+                      views::MaximumFlexSizeRule::kPreferred)
+                      .WithWeight(0));
   CreateActions();
 
   // TODO(pbos): Consider splitting out tab-strip observing into another class.

chrome/browser/ui/views/toolbar/toolbar_icon_container_view.h

@@ -9,6 +9,8 @@
 #include "ui/gfx/animation/animation_delegate.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/controls/button/button_observer.h"
+#include "ui/views/layout/animating_layout_manager.h"
+#include "ui/views/layout/flex_layout.h"
 #include "ui/views/view.h"
 
 // A general view container for any type of toolbar icons.
@@ -53,6 +55,17 @@ class ToolbarIconContainerView : public views::View,
 
   bool uses_highlight() { return uses_highlight_; }
 
+  // Provides access to the animating layout manager for subclasses.
+  views::AnimatingLayoutManager* animating_layout_manager() {
+    return static_cast<views::AnimatingLayoutManager*>(GetLayoutManager());
+  }
+
+  // Provides access to the flex layout in the animating layout manager.
+  views::FlexLayout* target_layout_manager() {
+    return static_cast<views::FlexLayout*>(
+        animating_layout_manager()->target_layout_manager());
+  }
+
   static const char kToolbarIconContainerViewClassName[];
 
  protected:

chrome/browser/ui/views/toolbar/toolbar_view.cc

@@ -707,10 +707,7 @@ void ToolbarView::InitLayout() {
           views::MinimumFlexSizeRule::kScaleToMinimum,
           views::MaximumFlexSizeRule::kUnbounded)
           .WithOrder(2);
-  const views::FlexSpecification browser_actions_flex_rule =
-      views::FlexSpecification::ForCustomRule(
-          BrowserActionsContainer::GetFlexRule())
-          .WithOrder(3);
+  constexpr int kExtensionsFlexOrder = 3;
 
   layout_manager_ = SetLayoutManager(std::make_unique<views::FlexLayout>());
 
@@ -724,11 +721,25 @@ void ToolbarView::InitLayout() {
                              gfx::Insets(0, location_bar_margin));
 
   if (browser_actions_) {
+    const views::FlexSpecification browser_actions_flex_rule =
+        views::FlexSpecification::ForCustomRule(
+            BrowserActionsContainer::GetFlexRule())
+            .WithOrder(kExtensionsFlexOrder);
+
     browser_actions_->SetProperty(views::kFlexBehaviorKey,
                                   browser_actions_flex_rule);
     browser_actions_->SetProperty(views::kMarginsKey, gfx::Insets());
     browser_actions_->SetProperty(views::kInternalPaddingKey,
                                   gfx::Insets(0, location_bar_margin));
+  } else if (extensions_container_) {
+    const views::FlexSpecification extensions_flex_rule =
+        views::FlexSpecification::ForCustomRule(
+            extensions_container_->animating_layout_manager()
+                ->GetDefaultFlexRule())
+            .WithOrder(kExtensionsFlexOrder);
+
+    extensions_container_->SetProperty(views::kFlexBehaviorKey,
+                                       extensions_flex_rule);
   }
 
   if (toolbar_account_icon_container_) {