Fix Entry/SearchBar color issues (#306)

* Fix disappearing Entry text on UWP Anniversary Edition
Fix background color reversion bug in UWP Phone
Move SearchBar styling on UWP to its own file
Make foreground/background color changes on UWP SearchBar/Entry consistent
Fix SearchBar color toggle bug on WP8

* Temporarily moving SDK target to previous version

* Fix build error on OSX

.nuspec/Xamarin.Forms.nuspec

@@ -239,6 +239,7 @@
     <file src="..\Xamarin.Forms.Platform.UAP\bin\$Configuration$\PageControl.xbf" target="lib\uap10.0\Xamarin.Forms.Platform.UAP" />
     <file src="..\Xamarin.Forms.Platform.UAP\bin\$Configuration$\Resources.xbf" target="lib\uap10.0\Xamarin.Forms.Platform.UAP" />
     <file src="..\Xamarin.Forms.Platform.UAP\bin\$Configuration$\FormsTextBoxStyle.xbf" target="lib\uap10.0\Xamarin.Forms.Platform.UAP" />
+	  <file src="..\Xamarin.Forms.Platform.UAP\bin\$Configuration$\AutoSuggestStyle.xbf" target="lib\uap10.0\Xamarin.Forms.Platform.UAP" />
 
     <file src="..\Xamarin.Forms.Core\bin\$Configuration$\Xamarin.Forms.Core.dll" target="lib\uap10.0" />
     <file src="..\docs\Xamarin.Forms.Core.xml" target="lib\uap10.0" />

Xamarin.Forms.ControlGallery.WindowsUniversal/Xamarin.Forms.ControlGallery.WindowsUniversal.csproj

@@ -12,7 +12,7 @@
     <AssemblyName>Xamarin.Forms.ControlGallery.WindowsUniversal</AssemblyName>
     <DefaultLanguage>en-US</DefaultLanguage>
     <TargetPlatformIdentifier>UAP</TargetPlatformIdentifier>
-    <TargetPlatformVersion>10.0.10240.0</TargetPlatformVersion>
+    <TargetPlatformVersion>10.0.10586.0</TargetPlatformVersion>
     <TargetPlatformMinVersion>10.0.10240.0</TargetPlatformMinVersion>
     <MinimumVisualStudioVersion>14</MinimumVisualStudioVersion>
     <EnableDotNetNativeCompatibleProfile>true</EnableDotNetNativeCompatibleProfile>

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/DefaultColorToggleTest.cs

@@ -58,7 +58,7 @@ static ContentPage PasswordPage()
 
 		static ContentPage SearchBarPage()
 		{
-			var searchbarTextColorDefaultToggle = new Entry() { Text = "Default SearchBar Text Color" };
+			var searchbarTextColorDefaultToggle = new SearchBar() { Text = "Default SearchBar Text Color" };
 			var searchbarTextColorToggleButton = new Button() { Text = "Toggle SearchBar Color" };
 			searchbarTextColorToggleButton.Clicked += (sender, args) => {
 				if (searchbarTextColorDefaultToggle.TextColor.IsDefault)
@@ -73,7 +73,7 @@ static ContentPage SearchBarPage()
 				}
 			};
 
-			var searchbarPlaceholderColorDefaultToggle = new Entry() { Placeholder = "Default Placeholder Color" };
+			var searchbarPlaceholderColorDefaultToggle = new SearchBar() { Placeholder = "Default Placeholder Color" };
 			var searchbarPlaceholderToggleButton = new Button() { Text = "Toggle Placeholder Color" };
 			searchbarPlaceholderToggleButton.Clicked += (sender, args) => {
 				if (searchbarPlaceholderColorDefaultToggle.PlaceholderColor.IsDefault)

Xamarin.Forms.Platform.UAP/FormsTextBoxStyle.xaml

@@ -8,14 +8,16 @@
 		<Setter Property="MinWidth" Value="{ThemeResource TextControlThemeMinWidth}" />
 		<Setter Property="MinHeight" Value="{ThemeResource TextControlThemeMinHeight}" />
 		<Setter Property="Foreground" Value="{ThemeResource SystemControlForegroundBaseHighBrush}" />
+		<Setter Property="ForegroundFocusBrush" Value="{ThemeResource SystemControlForegroundChromeBlackHighBrush}" />
+		<Setter Property="PlaceholderForegroundBrush" Value="{ThemeResource SystemControlPageTextBaseMediumBrush}" />
+		<Setter Property="PlaceholderForegroundFocusBrush" Value="{ThemeResource SystemControlPageTextChromeBlackMediumLowBrush}" />
 		<Setter Property="Background" Value="{ThemeResource SystemControlBackgroundAltHighBrush}" />
 		<Setter Property="BackgroundFocusBrush" Value="{ThemeResource SystemControlBackgroundChromeWhiteBrush}" />
 		<Setter Property="BorderBrush" Value="{ThemeResource SystemControlForegroundChromeDisabledLowBrush}" />
 		<Setter Property="SelectionHighlightColor" Value="{ThemeResource SystemControlHighlightAccentBrush}" />
 		<Setter Property="BorderThickness" Value="{ThemeResource TextControlBorderThemeThickness}" />
 		<Setter Property="FontFamily" Value="{ThemeResource ContentControlThemeFontFamily}" />
 		<Setter Property="FontSize" Value="{ThemeResource ControlContentThemeFontSize}" />
-		<Setter Property="PlaceholderForegroundBrush" Value="{ThemeResource SystemControlPageTextBaseMediumBrush}" />
 		<Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Hidden" />
 		<Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Hidden" />
 		<Setter Property="ScrollViewer.IsDeferredScrollingEnabled" Value="False" />
@@ -123,7 +125,7 @@
 									<Storyboard>
 										<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground"
 										                               Storyboard.TargetName="PlaceholderTextContentPresenter">
-											<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlPageTextChromeBlackMediumLowBrush}" />
+											<DiscreteObjectKeyFrame KeyTime="0" Value="{Binding PlaceholderForegroundFocusBrush, RelativeSource={RelativeSource TemplatedParent}}" />
 										</ObjectAnimationUsingKeyFrames>
 										<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background"
 										                               Storyboard.TargetName="BackgroundElement">
@@ -137,7 +139,7 @@
 											<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlHighlightAccentBrush}" />
 										</ObjectAnimationUsingKeyFrames>
 										<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentElement">
-											<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlForegroundChromeBlackHighBrush}" />
+											<DiscreteObjectKeyFrame KeyTime="0" Value="{Binding ForegroundFocusBrush, RelativeSource={RelativeSource TemplatedParent}}" />
 										</ObjectAnimationUsingKeyFrames>
 										<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="RequestedTheme"
 										                               Storyboard.TargetName="ContentElement">