[iOS] Adjust pinnedYOffset value to neareset pixel

This CL makes sure that the value returned by -pinnedYOffset is adjusted
to the nearest pixel. This is because when the content size isn't the
default one, the value isn't adjusted on a pixel. When it is used to
compare to the scroll value of the collection view, this gap prevents
the collection view from being considered as completely scrolled.

Bug: 905276
Change-Id: Ia44de6063b039a022fcde95e015c3e7df4259308
Reviewed-on: https://chromium-review.googlesource.com/c/1337490
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608748}

ios/chrome/browser/ui/content_suggestions/content_suggestions_collection_utils.mm

@@ -113,7 +113,8 @@ CGFloat doodleTopMargin(BOOL toolbarPresent, CGFloat topInset) {
   if (!IsCompactWidth() && !IsCompactHeight())
     return kDoodleTopMarginRegularXRegular;
   return topInset + kDoodleTopMarginOther +
-         kDoodleScaledTopMarginOther * SystemSuggestedFontSizeMultiplier();
+         AlignValueToPixel(kDoodleScaledTopMarginOther *
+                           SystemSuggestedFontSizeMultiplier());
 }
 
 CGFloat searchFieldTopMargin() {

ios/chrome/browser/ui/content_suggestions/content_suggestions_header_view_controller.mm

@@ -26,6 +26,7 @@
 #import "ios/chrome/browser/ui/toolbar/toolbar_utils.h"
 #import "ios/chrome/browser/ui/url_loader.h"
 #import "ios/chrome/browser/ui/util/named_guide.h"
+#include "ios/chrome/browser/ui/util/ui_util.h"
 #import "ios/chrome/browser/ui/util/uikit_ui_util.h"
 #import "ios/chrome/common/ui_util/constraints_ui_util.h"
 #include "ios/chrome/grit/ios_strings.h"
@@ -197,7 +198,7 @@ using base::UserMetricsAction;
                [self topInset];
   }
 
-  return offsetY;
+  return AlignValueToPixel(offsetY);
 }
 
 - (CGFloat)headerHeight {

ios/chrome/browser/ui/toolbar/toolbar_utils.h

@@ -12,14 +12,15 @@
 CGFloat ToolbarClampedFontSizeMultiplier(UIContentSizeCategory category);
 
 // Returns the height of the toolbar when it is collapsed, based on the current
-// |category|.
+// |category|, rounded to the nearest lower pixel.
 CGFloat ToolbarCollapsedHeight(UIContentSizeCategory category);
 
 // Returns the height of the toolbar when it is expanded, based on the current
-// |category|.
+// |category|, rounded to the nearest lower pixel.
 CGFloat ToolbarExpandedHeight(UIContentSizeCategory category);
 
-// Returns the height of the location bar, based on the |category|.
+// Returns the height of the location bar, based on the |category|, rounded to
+// the nearest lower pixel.
 CGFloat LocationBarHeight(UIContentSizeCategory category);
 
 #endif  // IOS_CHROME_BROWSER_UI_TOOLBAR_TOOLBAR_UTILS_H_

ios/chrome/browser/ui/toolbar/toolbar_utils.mm

@@ -62,5 +62,5 @@ CGFloat LocationBarHeight(UIContentSizeCategory category) {
       (kLocationBarVerticalMarginDynamicType +
        kAdaptiveLocationBarVerticalMargin);
   verticalMargin = verticalMargin + dynamicTypeVerticalAdjustment;
-  return ToolbarExpandedHeight(category) - verticalMargin;
+  return AlignValueToPixel(ToolbarExpandedHeight(category) - verticalMargin);
 }