build: remove enable_picture_in_picture build flag (#38620)

Co-authored-by: Milan Burda <miburda@microsoft.com>

shell/browser/api/electron_api_web_contents.cc

@@ -23,6 +23,7 @@
 #include "base/threading/scoped_blocking_call.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/picture_in_picture/picture_in_picture_window_manager.h"
 #include "chrome/browser/ui/exclusive_access/exclusive_access_manager.h"
 #include "chrome/browser/ui/views/eye_dropper/eye_dropper.h"
 #include "chrome/common/pref_names.h"
@@ -184,10 +185,6 @@
 #endif
 #endif  // BUILDFLAG(ENABLE_PRINTING)
 
-#if BUILDFLAG(ENABLE_PICTURE_IN_PICTURE)
-#include "chrome/browser/picture_in_picture/picture_in_picture_window_manager.h"
-#endif
-
 #if BUILDFLAG(ENABLE_PDF_VIEWER)
 #include "components/pdf/browser/pdf_web_contents_helper.h"  // nogncheck
 #include "shell/browser/electron_pdf_web_contents_helper_client.h"
@@ -3896,18 +3893,12 @@ bool WebContents::TakeFocus(content::WebContents* source, bool reverse) {
 
 content::PictureInPictureResult WebContents::EnterPictureInPicture(
     content::WebContents* web_contents) {
-#if BUILDFLAG(ENABLE_PICTURE_IN_PICTURE)
   return PictureInPictureWindowManager::GetInstance()
       ->EnterVideoPictureInPicture(web_contents);
-#else
-  return content::PictureInPictureResult::kNotSupported;
-#endif
 }
 
 void WebContents::ExitPictureInPicture() {
-#if BUILDFLAG(ENABLE_PICTURE_IN_PICTURE)
   PictureInPictureWindowManager::GetInstance()->ExitPictureInPicture();
-#endif
 }
 
 void WebContents::DevToolsSaveToFile(const std::string& url,

shell/browser/electron_browser_client.cc

@@ -186,7 +186,7 @@
 #include "components/crash/core/app/crashpad.h"        // nogncheck
 #endif
 
-#if BUILDFLAG(ENABLE_PICTURE_IN_PICTURE) && BUILDFLAG(IS_WIN)
+#if BUILDFLAG(IS_WIN)
 #include "chrome/browser/ui/views/overlay/video_overlay_window_views.h"
 #include "shell/browser/browser.h"
 #include "ui/aura/window.h"
@@ -422,9 +422,6 @@ void ElectronBrowserClient::OverrideWebkitPrefs(
   prefs->default_minimum_page_scale_factor = 1.f;
   prefs->default_maximum_page_scale_factor = 1.f;
   prefs->navigate_on_drag_drop = false;
-#if !BUILDFLAG(ENABLE_PICTURE_IN_PICTURE)
-  prefs->picture_in_picture_enabled = false;
-#endif
 
   ui::NativeTheme* native_theme = ui::NativeTheme::GetInstanceForNativeUi();
   prefs->preferred_color_scheme =
@@ -674,7 +671,6 @@ bool ElectronBrowserClient::CanCreateWindow(
   return false;
 }
 
-#if BUILDFLAG(ENABLE_PICTURE_IN_PICTURE)
 std::unique_ptr<content::VideoOverlayWindow>
 ElectronBrowserClient::CreateWindowForVideoPictureInPicture(
     content::VideoPictureInPictureWindowController* controller) {
@@ -692,7 +688,6 @@ ElectronBrowserClient::CreateWindowForVideoPictureInPicture(
 #endif
   return overlay_window;
 }
-#endif
 
 void ElectronBrowserClient::GetAdditionalAllowedSchemesForFileSystem(
     std::vector<std::string>* additional_schemes) {

shell/browser/electron_browser_client.h

@@ -160,11 +160,9 @@ class ElectronBrowserClient : public content::ContentBrowserClient,
                        bool user_gesture,
                        bool opener_suppressed,
                        bool* no_javascript_access) override;
-#if BUILDFLAG(ENABLE_PICTURE_IN_PICTURE)
   std::unique_ptr<content::VideoOverlayWindow>
   CreateWindowForVideoPictureInPicture(
       content::VideoPictureInPictureWindowController* controller) override;
-#endif
   void GetAdditionalAllowedSchemesForFileSystem(
       std::vector<std::string>* additional_schemes) override;
   void GetAdditionalWebUISchemes(

shell/browser/feature_list.cc

@@ -36,10 +36,6 @@ void InitializeFeatureList() {
   disable_features +=
       std::string(",") + features::kSpareRendererForSitePerProcess.name;
 
-#if !BUILDFLAG(ENABLE_PICTURE_IN_PICTURE)
-  disable_features += std::string(",") + media::kPictureInPicture.name;
-#endif
-
 #if BUILDFLAG(IS_WIN)
   disable_features +=
       // Disable async spellchecker suggestions for Windows, which causes