Bug 645288 - Register Firefox as a webm capable player on Windows. r=rstrong

browser/installer/windows/nsis/installer.nsi

@@ -123,6 +123,7 @@ VIAddVersionKey "OriginalFilename" "setup.exe"
 !insertmacro UnloadUAC
 !insertmacro WriteRegStr2
 !insertmacro WriteRegDWORD2
+!insertmacro CheckIfRegistryKeyExists
 
 !include shared.nsh
 

browser/installer/windows/nsis/shared.nsh

@@ -279,6 +279,12 @@
     WriteRegStr SHCTX "$0\.xhtml" "" "FirefoxHTML"
   ${EndIf}
 
+  ; Only add webm if it's not present
+  ${CheckIfRegistryKeyExists} "$0" ".webm" $7
+  ${If} $7 == "false"
+    WriteRegStr SHCTX "$0\.webm"  "" "FirefoxHTML"
+  ${EndIf}
+
   StrCpy $3 "$\"%1$\",,0,0,,,,"
 
   ; An empty string is used for the 5th param because FirefoxHTML is not a

browser/installer/windows/nsis/uninstaller.nsi

@@ -107,6 +107,7 @@ VIAddVersionKey "OriginalFilename" "helper.exe"
 !insertmacro UnloadUAC
 !insertmacro WriteRegDWORD2
 !insertmacro WriteRegStr2
+!insertmacro CheckIfRegistryKeyExists
 
 !insertmacro un.ChangeMUIHeaderImage
 !insertmacro un.CheckForFilesInUse
@@ -266,6 +267,7 @@ Section "Uninstall"
     ${un.RegCleanFileHandler}  ".shtml" "FirefoxHTML"
     ${un.RegCleanFileHandler}  ".xht"   "FirefoxHTML"
     ${un.RegCleanFileHandler}  ".xhtml" "FirefoxHTML"
+    ${un.RegCleanFileHandler}  ".webm"  "FirefoxHTML"
   ${EndIf}
 
   SetShellVarContext all  ; Set SHCTX to HKLM