Follow Google's branding guideline

#1582

Signed-off-by: Tamotsu Takahashi <ttakah@gmail.com>

Author: Tamotsu Takahashi

public/views/shared/signin-modal.ejs

@@ -44,8 +44,8 @@
                 </a>
                 <% } %>
                 <% if (authProviders.google) { %>
-                <a href="<%- serverURL %>/auth/google" class="btn btn-lg btn-block btn-login-method btn-google">
-                    <i class="fa fa-google"></i> <%= __('Sign in via %s', 'Google') %>
+                <a href="<%- serverURL %>/auth/google" class="btn btn-lg btn-block" style="color: #fff; background-color: #4285F4; vertical-align: middle; font-size: 14px;">
+                    <svg aria-hidden="true" width="18" height="18" viewBox="0 0 18 18" style="vertical-align: middle; margin-right: 24; background-color=#fff"><path d="M16.51 8H8.98v3h4.3c-.18 1-.74 1.48-1.6 2.04v2.01h2.6a7.8 7.8 0 002.38-5.88c0-.57-.05-.66-.15-1.18z" fill="#4285F4"></path><path d="M8.98 17c2.16 0 3.97-.72 5.3-1.94l-2.6-2a4.8 4.8 0 01-7.18-2.54H1.83v2.07A8 8 0 008.98 17z" fill="#34A853"></path><path d="M4.5 10.52a4.8 4.8 0 010-3.04V5.41H1.83a8 8 0 000 7.18l2.67-2.07z" fill="#FBBC05"></path><path d="M8.98 4.18c1.17 0 2.23.4 3.06 1.2l2.3-2.3A8 8 0 001.83 5.4L4.5 7.49a4.77 4.77 0 014.48-3.3z" fill="#EA4335"></path></svg> <%= __('Sign in via %s', 'Google') %>
                 </a>
                 <% } %>
                 <% if (authProviders.saml) { %>