GMail - waiting for the page for fully loaded - selenium

Question

I am trying to automate gmail page (for some kind of email verification), after input username and password, I want to wait the page to fully loaded before continuing to my next action.
This is what I tried:
Selenium2Library.Input Text //input[contains(#id, "identifierId")] ${local_email_username}
Selenium2Library.Click Element //span[text()="Berikutnya"]
Sleep 2s
Selenium2Library.Wait Until Element Is Visible //input[contains(#name, "password")] timeout=30s
Selenium2Library.Input Password //input[contains(#name, "password")] ${local_email_password}
Selenium2Library.Click Element //span[text()="Berikutnya"]
Sleep 2s
Selenium2Library.Wait Until Element Is Visible //input[contains(#aria-label, "Search")] timeout=30s
### should be logged in to gmail
Log >>> logged in to gmail. sleeping..
Sleep 5s
### make sure the email page fully loaded
Log >>> making sure the email page fully loaded.. waiting new conversation button appeared
Comment Wait Until Keyword Succeeds 10x 2s Selenium2Library.Page Should Contain ${email_name}
Wait Until Keyword Succeeds 20x 3s Selenium2Library.Page Should Contain Element //button[contains(#title, 'New conversation')]
Log >>> email page fully loaded. start searching activation email...
What I want to achieve is waiting for the new conversation button, that indicates that page is fully loaded (//button[contains(#title, 'New conversation')])
The problem is the script never finds the button. I tried to inspect and search for that xpath, and the element found.
Is there any solution for that?
Update:
i tried using Select Frame like this.. like #Gaurav said.. here's the code:|
Selenium2Library.Select Frame ${iframe_locator}
Wait Until Keyword Succeeds 20x 3s Selenium2Library.Page Should Contain Element //button[contains(#title, 'New conversation')]
Selenium2Library.Unselect Frame
where ${iframe_locator} is //body/div[7]/div[3]/div[1]/div[2]/div[1]/div[1]/div[3]/div[1]/div[1]/div[2]/div[1]/iframe[2]
but still no luck

Answer 1

The button is in iFrame, so you need to switch to that iFrame(there might be more iframes, so you need to switch to that specific one) and the look for //button[contains(#title, 'New conversation')]
Here is Corresponding Java Implementation
#Test
public void newConversation() throws IOException, InterruptedException{
driver.get("https://www.google.com/intl/hi/gmail/about/");
driver.findElement(By.linkText("प्रवेश करें")).click();
driver.findElement(By.id("identifierId")).sendKeys("*********#gmail.com");
driver.findElement(By.id("identifierNext")).click();
Thread.sleep(30000);
driver.switchTo().frame(5);
WebElement element = driver.findElement(By.xpath("//div[contains(#aria-label,'Change profile picture')]"));
Actions action = new Actions(driver);
action.moveToElement(element).build().perform();
driver.findElement(By.xpath("//button[contains(#title,'New conversation')]")).click();
}