Start in background mode

specs/StartInBackgroundMode.md

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+CreationPriority
+===
+
+# Background
+WebView2 has functionality enabled by default which raises the launch priority of WebView2
+processes to ensure that WebView2 processes are given higher CPU priority and access to resources
+during creation, and that can bring improvements on time spent creating a WebView2 instance. Since 
+this improvement is at the cost of taking higher CPU priority, we introduce the `CreationPriority` 
+property to give developers an option to decide by themselves.
+
+# Description
+* Setting `CreationPriority` to `COREWEBVIEW2_CREATION_PRIORITY_NORMAL` will signal WebView2 
+to have normal priority compared to other processes during the creation of the WebView2 browser 
+process.
+* Setting `CreationPriority` to `COREWEBVIEW2_CREATION_PRIORITY_HIGH` will attempt to enable 
+raise the priority of the creation of the WebView2 browser process.
+* Default value is `COREWEBVIEW2_CREATION_PRIORITY_HIGH`.
+# Examples
+## Win32 C++
+```cpp
+auto options = Microsoft::WRL::Make<CoreWebView2EnvironmentOptions>();
+/// Set the WebView2 browser process to have normal priority during 
+/// creation, which avoids to impact other host application 
+/// processes acquiring system resources.
+options->put_CreationPriority(COREWEBVIEW2_CREATION_PRIORITY_NORMAL);
+HRESULT hr = CreateCoreWebView2EnvironmentWithOptions(
+ nullptr, m_userDataFolder.c_str(), options.Get(),
+ Callback<ICoreWebView2CreateCoreWebView2EnvironmentCompletedHandler>(
+ this, &AppWindow::OnCreateEnvironmentCompleted).Get());
+```
+## WinRT and .NET
+```c#
+CoreWebView2EnvironmentOptions options = new CoreWebView2EnvironmentOptions();
+options.CreationPriority = COREWEBVIEW2_CREATION_PRIORITY_NORMAL;
+CoreWebView2Environment Environment = 
+ await CoreWebView2Environment.CreateAsync(
+ BrowserExecutableFolder, UserDataFolder, options)
+```
+
+
+# API Details
+## Win32 C++
+```cpp
+/// Specifies the type of webview2 creation priority for the
+/// `ICoreWebView2EnvironmentOptions3:CreationPriority` option.
+[v1_enum]
+typedef enum COREWEBVIEW2_CREATION_PRIORITY {
+ COREWEBVIEW2_CREATION_PRIORITY_NORMAL,
+ COREWEBVIEW2_CREATION_PRIORITY_HIGH,
+} COREWEBVIEW2_CREATION_PRIORITY;
+
+[uuid(efb58776-32bd-11ed-a261-0242ac120002), object, pointer_default(unique)]
+interface ICoreWebView2EnvironmentOptions3 : ICoreWebView2EnvironmentOptions2 {
+
+ /// Gets the creation priority for webview2 creation.
+ ///
+ /// \snippet AppWindow.cpp CreateCoreWebView2EnvironmentWithOptions
+ // MSOWNERS: wangsongjin@microsoft.com
+ [propget] HRESULT CreationPriority([out, retval] COREWEBVIEW2_CREATION_PRIORITY* creationPriority);
+
+ /// Sets the `CreationPriority` property.
+ /// The `CreationPriority` property specifies the priority used during the WebView2 
+ /// browser process creation.
+ /// Set `CreationPriority` to `COREWEBVIEW2_CREATION_PRIORITY_NORMAL` will create the
+ /// WebView2 browser process with normal priority.
+ /// Set `CreationPriority` to `COREWEBVIEW2_CREATION_PRIORITY_HIGH` will attempt to
+ /// create the WebView2 browser process with high priority.
+ /// Default is `COREWEBVIEW2_CREATION_PRIORITY_HIGH`.
+ /// Note that the host app's priority must be at least normal for 
+ /// `COREWEBVIEW2_CREATION_PRIORITY_HIGH` to be applied. Otherwise the WebView2 browser 
+ /// process still get created with normal priority even with `COREWEBVIEW2_CREATION_PRIORITY_HIGH` 
+ /// setting. Additionally, currently `CreationPriority` only applies to the creation of the 
+ /// WebView2 browser process. `CreationPriority` may be broadened to apply to other parts of 
+ /// WebView2 creation in the future.
+ // MSOWNERS: wangsongjin@microsoft.com
+ [propput] HRESULT CreationPriority([in] COREWEBVIEW2_CREATION_PRIORITY creationPriority);
+}
+```
+## WinRT and .NET
+```c#
+namespace Microsoft.Web.WebView2.Core
+{
+ enum CoreWebView2CreationPriority
+ {
+ Normal = 0,
+ High = 1,
+ };
+
+ runtimeclass CoreWebView2EnvironmentOptions
+ {
+
+ // ...
+ [interface_name("Microsoft.Web.WebView2.Core.ICoreWebView2EnvironmentOptions3")]
+ {
+
+ CoreWebView2CreationPriority CreationPriority { get; set; };
+
+ }
+ }
+}
+```