Themes: Make toolbar highlights optional

Following Diana's flat style motto "remove unnecessary lines", this
patch makes highlights and shadows in the toolbars optional, and removes
them for the new flat theme.

"default" and "dark" are not affected by this change.

Change-Id: Iadbbaa669e318406a154fed3e07890fd40f5f621
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

share/qtcreator/themes/dark.creatortheme

@@ -171,6 +171,7 @@ DrawIndicatorBranch=true
 DrawProgressBarSunken=false
 DrawSearchResultWidgetFrame=false
 DrawTargetSelectorBottom=false
+DrawToolBarHighlights=true
 ApplyThemePaletteGlobally=true
 FlatSideBarIcons=true
 FlatProjectsMode=true

share/qtcreator/themes/darkframe.creatortheme

@@ -173,6 +173,7 @@ DrawIndicatorBranch=true
 DrawProgressBarSunken=false
 DrawSearchResultWidgetFrame=false
 DrawTargetSelectorBottom=false
+DrawToolBarHighlights=false
 ApplyThemePaletteGlobally=false
 FlatSideBarIcons=true
 FlatProjectsMode=false

share/qtcreator/themes/default.creatortheme

@@ -165,6 +165,7 @@ DrawIndicatorBranch=false
 DrawProgressBarSunken=true
 DrawSearchResultWidgetFrame=true
 DrawTargetSelectorBottom=true
+DrawToolBarHighlights=true
 ApplyThemePaletteGlobally=false
 FlatSideBarIcons=false
 FlatProjectsMode=false

src/libs/utils/theme/theme.h

@@ -256,6 +256,7 @@ public:
         DrawSearchResultWidgetFrame,
         DrawProgressBarSunken,
         DrawIndicatorBranch,
+        DrawToolBarHighlights,
         ComboBoxDrawTextShadow,
         DerivePaletteFromTheme,
         ApplyThemePaletteGlobally,

src/plugins/coreplugin/manhattanstyle.cpp

@@ -830,6 +830,7 @@ void ManhattanStyle::drawControl(ControlElement element, const QStyleOption *opt
             else
                 StyleHelper::verticalGradient(painter, gradientSpan, rect, drawLightColored);
 
+            if (creatorTheme()->flag(Theme::DrawToolBarHighlights)) {
                 if (!drawLightColored)
                     painter->setPen(StyleHelper::borderColor());
                 else
@@ -858,6 +859,7 @@ void ManhattanStyle::drawControl(ControlElement element, const QStyleOption *opt
                     painter->drawLine(borderRect.topRight(), borderRect.bottomRight());
                 }
             }
+        }
         break;
 
     default: