Add devtools support on Android/iOS (#548)

.changes/mobile-devtools.md

@@ -0,0 +1,5 @@
+---
+"wry": patch
+---
+
+Add devtools support on Android/iOS.

src/webview/android/mod.rs

@@ -60,6 +60,7 @@ impl InnerWebView {
       custom_protocols,
       initialization_scripts,
       ipc_handler,
+      devtools,
       ..
     } = self.attributes;
 
@@ -69,6 +70,19 @@ impl InnerWebView {
       *ipc = i;
     }
 
+    if devtools {
+      #[cfg(any(debug_assertions, feature = "devtools"))]
+      {
+        let class = env.find_class("android/webkit/WebView")?;
+        env.call_static_method(
+          class,
+          "setWebContentsDebuggingEnabled",
+          "(Z)V",
+          &[devtools.into()],
+        )?;
+      }
+    }
+
     if let Some(u) = url {
       let mut url_string = String::from(u.as_str());
       let schemes = custom_protocols

src/webview/mod.rs

@@ -143,11 +143,14 @@ pub struct WebViewAttributes {
   /// Enable web inspector which is usually called dev tool.
   ///
   /// Note this only enables dev tool to the webview. To open it, you can call
-  /// [`WebView::devtool`], or right click the page and open it from the context menu.
+  /// [`WebView::open_devtools`], or right click the page and open it from the context menu.
   ///
-  /// # Warning
-  /// This will call private functions on **macOS**. It's still enabled if set in **debug** build on mac,
-  /// but requires `devtool` feature flag to actually enable it in **release** build.
+  /// ## Platform-specific
+  ///
+  /// - macOS: This will call private functions on **macOS**. It's still enabled if set in **debug** build on mac,
+  /// but requires `devtools` feature flag to actually enable it in **release** build.
+  /// - Android: Open `chrome://inspect/#devices` in Chrome to get the devtools window. Wry's `WebView` devtools API isn't supported on Android.
+  /// - iOS: Open Safari > Develop > [Your Device Name] > [Your WebView] to get the devtools window.
   pub devtools: bool,
 }
 
@@ -321,9 +324,12 @@ impl<'a> WebViewBuilder<'a> {
   /// Note this only enables dev tool to the webview. To open it, you can call
   /// [`WebView::open_devtools`], or right click the page and open it from the context menu.
   ///
-  /// # Warning
-  /// This will call private functions on **macOS**. It's still enabled if set in **debug** build on mac,
+  /// ## Platform-specific
+  ///
+  /// - macOS: This will call private functions on **macOS**. It's still enabled if set in **debug** build on mac,
   /// but requires `devtools` feature flag to actually enable it in **release** build.
+  /// - Android: Open `chrome://inspect/#devices` in Chrome to get the devtools window. Wry's `WebView` devtools API isn't supported on Android.
+  /// - iOS: Open Safari > Develop > [Your Device Name] > [Your WebView] to get the devtools window.
   pub fn with_devtools(mut self, devtools: bool) -> Self {
     self.webview.devtools = devtools;
     self