chromium: Add chrome-virtual-keyboard recipe

chrome-virtual-keyboard is an extension to chromium that
has a javascript on-screen keyboard that allow users
to use chromium without a physical keyboard.

According to chrome webstore, there are over 700K users.

limitations:
    * upstream hasn't maintained this extension for a long time
    * not all textbox will work, notably iframes

How to use:
    Enable through chromium PACKAGECONFIG vkeyboard-extension.

leveraging the chromium flag:
--extension-load="" to load a local unpacked extension.

Signed-off-by: Yi Fan Yu <yifan.yu@windriver.com>

Author: Yi Fan Yu

meta-chromium/classes/chromium-extension-package.bbclass

@@ -0,0 +1,5 @@
+# class for defining extension dir for chromium
+
+CHROMIUM_EXTENSION_DIR = "${datadir}/chromium-extension"
+
+VIRTUAL_KEYBOARD_DIR = "${CHROMIUM_EXTENSION_DIR}/chrome-virtual-keyboard"

meta-chromium/recipes-browser/chromium-extensions/chrome-virtual-keyboard_git.bb

@@ -0,0 +1,28 @@
+SUMMARY = "Chromium Virtual Keyboard"
+DESCRIPTION = "Virtual Keyboard Extension for Chromium/Chrome"
+HOMEPAGE = "https://apps.xontab.com/VirtualKeyboard"
+LICENSE = "MIT"
+LIC_FILES_CHKSUM = "file://LICENSE;md5=a8366463bacd4f2ec5edd419e8a113ff"
+
+SRC_URI = " \
+            git://github.com/xontab/${BPN}.git \
+"
+SRCREV = "e2b9adf4885cc4ed600cd9bccb77e0df8ff549aa"
+S = "${WORKDIR}/git"
+PV = "1.11.3+git${SRCPV}"
+
+inherit allarch chromium-extension-package
+
+do_compile() {
+    :
+}
+do_install() {
+    install -d ${D}${CHROMIUM_EXTENSION_DIR}/
+    cp -r ${S} ${D}${CHROMIUM_EXTENSION_DIR}/${BPN}
+
+    # remove unecessary artifacts
+    rm  -f ${D}${CHROMIUM_EXTENSION_DIR}/${BPN}/_config.yml
+    rm  -rf ${D}${CHROMIUM_EXTENSION_DIR}/${BPN}/.git/
+}
+
+FILES_${PN} += "${CHROMIUM_EXTENSION_DIR}/${BPN}"

meta-chromium/recipes-browser/chromium/chromium-gn.inc

@@ -2,7 +2,7 @@ require chromium.inc
 require chromium-unbundle.inc
 require gn-utils.inc
 
-inherit features_check gtk-icon-cache qemu
+inherit features_check gtk-icon-cache qemu chromium-extension-package
 
 # The actual directory name in out/ is irrelevant for GN.
 OUTPUT_DIR = "out/Release"
@@ -116,14 +116,16 @@ PACKAGECONFIG[proprietary-codecs] = ' \
         ffmpeg_branding="Chrome" proprietary_codecs=true, \
         ffmpeg_branding="Chromium" proprietary_codecs=false \
 '
-
 # Disable VA-API by default. It is compile time enabled since M88, but it's not
 # desired to make all the users of the Chromium meta-browser recipe depend on
 # libva without a real need. Both X11 (non-Ozone) and Wayland (Ozone) can use it,
 # but remember to also use proprietary codecs so that H.264 is supported. Also note
 # that not all the hardware configs might be supported.
 PACKAGECONFIG[use-vaapi] = "use_vaapi=true,use_vaapi=false,libva"
 
+# chrome/chromium extension for virtual keyboard
+PACKAGECONFIG[vkeyboard-extension]= ",,,chrome-virtual-keyboard"
+
 # Base GN arguments, mostly related to features we want to enable or disable.
 GN_ARGS = " \
         ${PACKAGECONFIG_CONFARGS} \
@@ -309,10 +311,17 @@ GN_ARGS_append_armv6 += 'arm_use_neon=false'
 # https://github.com/gperftools/gperftools/issues/693
 GN_ARGS_append_libc-musl = ' use_allocator_shim=false'
 
+
+# Add chromium extensions here
+CHROMIUM_EXTENSIONS = " \
+        ${@bb.utils.contains('PACKAGECONFIG', 'vkeyboard-extension', '${VIRTUAL_KEYBOARD_DIR}', '', d)} \
+"
+
 CHROMIUM_EXTRA_ARGS ?= " \
         ${@bb.utils.contains('PACKAGECONFIG', 'use-egl', '--use-gl=egl', '', d)} \
         ${@bb.utils.contains('PACKAGECONFIG', 'impl-side-painting', '--enable-gpu-rasterization --enable-impl-side-painting', '', d)} \
         ${@bb.utils.contains('PACKAGECONFIG', 'kiosk-mode', '--kiosk --no-first-run --incognito', '', d)} \
+        --load-extension=${@",".join(d.getVar('CHROMIUM_EXTENSIONS').split())} \
 "
 
 # V8's JIT infrastructure requires binaries such as mksnapshot and
@@ -429,7 +438,7 @@ do_install() {
 
 	# Add extra command line arguments to the chromium-wrapper script by
 	# modifying the dummy "CHROME_EXTRA_ARGS" line
-	sed -i "s/^CHROME_EXTRA_ARGS=\"\"/CHROME_EXTRA_ARGS=\"${CHROMIUM_EXTRA_ARGS}\"/" ${D}${libdir}/chromium/chromium-wrapper
+	sed -i "s#^CHROME_EXTRA_ARGS=\"\"#CHROME_EXTRA_ARGS=\"${CHROMIUM_EXTRA_ARGS}\"#" ${D}${libdir}/chromium/chromium-wrapper
 
 	# This is ANGLE, not to be confused with the similarly named files under swiftshader/
 	if [ -e libEGL.so ]; then